2 * util/data/msgparse.c - parse wireformat DNS messages.
4 * Copyright (c) 2007, NLnet Labs. All rights reserved.
6 * This software is open source.
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
12 * Redistributions of source code must retain the above copyright notice,
13 * this list of conditions and the following disclaimer.
15 * Redistributions in binary form must reproduce the above copyright notice,
16 * this list of conditions and the following disclaimer in the documentation
17 * and/or other materials provided with the distribution.
19 * Neither the name of the NLNET LABS nor the names of its contributors may
20 * be used to endorse or promote products derived from this software without
21 * specific prior written permission.
23 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
24 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
25 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
26 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
27 * HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
28 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
29 * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
30 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
31 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
32 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
33 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
37 * Routines for message parsing a packet buffer to a descriptive structure.
40 #include "util/data/msgparse.h"
41 #include "util/data/msgreply.h"
42 #include "util/data/dname.h"
43 #include "util/data/packed_rrset.h"
44 #include "util/storage/lookup3.h"
45 #include "util/regional.h"
46 #include "sldns/rrdef.h"
47 #include "sldns/sbuffer.h"
48 #include "sldns/parseutil.h"
49 #include "sldns/wire2str.h"
51 /** smart comparison of (compressed, valid) dnames from packet */
53 smart_compare(sldns_buffer* pkt, uint8_t* dnow,
54 uint8_t* dprfirst, uint8_t* dprlast)
56 if(LABEL_IS_PTR(*dnow)) {
57 /* ptr points to a previous dname */
58 uint8_t* p = sldns_buffer_at(pkt, PTR_OFFSET(dnow[0], dnow[1]));
59 if( p == dprfirst || p == dprlast )
61 /* prev dname is also a ptr, both ptrs are the same. */
62 if(LABEL_IS_PTR(*dprlast) &&
63 dprlast[0] == dnow[0] && dprlast[1] == dnow[1])
66 return dname_pkt_compare(pkt, dnow, dprlast);
70 * Allocate new rrset in region, fill with data.
72 static struct rrset_parse*
73 new_rrset(struct msg_parse* msg, uint8_t* dname, size_t dnamelen,
74 uint16_t type, uint16_t dclass, hashvalue_type hash,
75 uint32_t rrset_flags, sldns_pkt_section section,
76 struct regional* region)
78 struct rrset_parse* p = regional_alloc(region, sizeof(*p));
80 p->rrset_bucket_next = msg->hashtable[hash & (PARSE_TABLE_SIZE-1)];
81 msg->hashtable[hash & (PARSE_TABLE_SIZE-1)] = p;
82 p->rrset_all_next = 0;
84 msg->rrset_last->rrset_all_next = p;
85 else msg->rrset_first = p;
90 p->dname_len = dnamelen;
92 p->rrset_class = dclass;
93 p->flags = rrset_flags;
104 /** See if next rrset is nsec at zone apex */
106 nsec_at_apex(sldns_buffer* pkt)
108 /* we are at ttl position in packet. */
109 size_t pos = sldns_buffer_position(pkt);
111 if(sldns_buffer_remaining(pkt) < 7) /* ttl+len+root */
113 sldns_buffer_skip(pkt, 4); /* ttl */;
114 rdatalen = sldns_buffer_read_u16(pkt);
115 if(sldns_buffer_remaining(pkt) < rdatalen) {
116 sldns_buffer_set_position(pkt, pos);
117 return 0; /* parse error happens later */
119 /* must validate the nsec next domain name format */
120 if(pkt_dname_len(pkt) == 0) {
121 sldns_buffer_set_position(pkt, pos);
122 return 0; /* parse error */
125 /* see if SOA bit is set. */
126 if(sldns_buffer_position(pkt) < pos+4+rdatalen) {
127 /* nsec type bitmap contains items */
128 uint8_t win, blen, bits;
129 /* need: windownum, bitmap len, firstbyte */
130 if(sldns_buffer_position(pkt)+3 > pos+4+rdatalen) {
131 sldns_buffer_set_position(pkt, pos);
132 return 0; /* malformed nsec */
134 win = sldns_buffer_read_u8(pkt);
135 blen = sldns_buffer_read_u8(pkt);
136 bits = sldns_buffer_read_u8(pkt);
137 /* 0window always first window. bitlen >=1 or parse
138 error really. bit 0x2 is SOA. */
139 if(win == 0 && blen >= 1 && (bits & 0x02)) {
140 sldns_buffer_set_position(pkt, pos);
145 sldns_buffer_set_position(pkt, pos);
149 /** Calculate rrset flags */
151 pkt_rrset_flags(sldns_buffer* pkt, uint16_t type, sldns_pkt_section sec)
154 if(type == LDNS_RR_TYPE_NSEC && nsec_at_apex(pkt)) {
155 f |= PACKED_RRSET_NSEC_AT_APEX;
156 } else if(type == LDNS_RR_TYPE_SOA && sec == LDNS_SECTION_AUTHORITY) {
157 f |= PACKED_RRSET_SOA_NEG;
163 pkt_hash_rrset(sldns_buffer* pkt, uint8_t* dname, uint16_t type,
164 uint16_t dclass, uint32_t rrset_flags)
166 /* note this MUST be identical to rrset_key_hash in packed_rrset.c */
167 /* this routine handles compressed names */
168 hashvalue_type h = 0xab;
169 h = dname_pkt_hash(pkt, dname, h);
170 h = hashlittle(&type, sizeof(type), h); /* host order */
171 h = hashlittle(&dclass, sizeof(dclass), h); /* netw order */
172 h = hashlittle(&rrset_flags, sizeof(uint32_t), h);
176 /** create partial dname hash for rrset hash */
177 static hashvalue_type
178 pkt_hash_rrset_first(sldns_buffer* pkt, uint8_t* dname)
180 /* works together with pkt_hash_rrset_rest */
181 /* note this MUST be identical to rrset_key_hash in packed_rrset.c */
182 /* this routine handles compressed names */
183 hashvalue_type h = 0xab;
184 h = dname_pkt_hash(pkt, dname, h);
188 /** create a rrset hash from a partial dname hash */
189 static hashvalue_type
190 pkt_hash_rrset_rest(hashvalue_type dname_h, uint16_t type, uint16_t dclass,
191 uint32_t rrset_flags)
193 /* works together with pkt_hash_rrset_first */
194 /* note this MUST be identical to rrset_key_hash in packed_rrset.c */
196 h = hashlittle(&type, sizeof(type), dname_h); /* host order */
197 h = hashlittle(&dclass, sizeof(dclass), h); /* netw order */
198 h = hashlittle(&rrset_flags, sizeof(uint32_t), h);
202 /** compare rrset_parse with data */
204 rrset_parse_equals(struct rrset_parse* p, sldns_buffer* pkt, hashvalue_type h,
205 uint32_t rrset_flags, uint8_t* dname, size_t dnamelen,
206 uint16_t type, uint16_t dclass)
208 if(p->hash == h && p->dname_len == dnamelen && p->type == type &&
209 p->rrset_class == dclass && p->flags == rrset_flags &&
210 dname_pkt_compare(pkt, dname, p->dname) == 0)
217 msgparse_hashtable_lookup(struct msg_parse* msg, sldns_buffer* pkt,
218 hashvalue_type h, uint32_t rrset_flags, uint8_t* dname,
219 size_t dnamelen, uint16_t type, uint16_t dclass)
221 struct rrset_parse* p = msg->hashtable[h & (PARSE_TABLE_SIZE-1)];
223 if(rrset_parse_equals(p, pkt, h, rrset_flags, dname, dnamelen,
226 p = p->rrset_bucket_next;
231 /** return type networkformat that rrsig in packet covers */
233 pkt_rrsig_covered(sldns_buffer* pkt, uint8_t* here, uint16_t* type)
235 size_t pos = sldns_buffer_position(pkt);
236 sldns_buffer_set_position(pkt, (size_t)(here-sldns_buffer_begin(pkt)));
237 /* ttl + len + size of small rrsig(rootlabel, no signature) */
238 if(sldns_buffer_remaining(pkt) < 4+2+19)
240 sldns_buffer_skip(pkt, 4); /* ttl */
241 if(sldns_buffer_read_u16(pkt) < 19) /* too short */ {
242 sldns_buffer_set_position(pkt, pos);
245 *type = sldns_buffer_read_u16(pkt);
246 sldns_buffer_set_position(pkt, pos);
250 /** true if covered type equals prevtype */
252 pkt_rrsig_covered_equals(sldns_buffer* pkt, uint8_t* here, uint16_t type)
255 if(pkt_rrsig_covered(pkt, here, &t) && t == type)
261 msgparse_bucket_remove(struct msg_parse* msg, struct rrset_parse* rrset)
263 struct rrset_parse** p;
264 p = &msg->hashtable[ rrset->hash & (PARSE_TABLE_SIZE-1) ];
267 *p = rrset->rrset_bucket_next;
270 p = &( (*p)->rrset_bucket_next );
274 /** change section of rrset from previous to current section */
276 change_section(struct msg_parse* msg, struct rrset_parse* rrset,
277 sldns_pkt_section section)
279 struct rrset_parse *p, *prev;
280 /* remove from list */
281 if(section == rrset->section)
283 p = msg->rrset_first;
287 if(prev) prev->rrset_all_next = p->rrset_all_next;
288 else msg->rrset_first = p->rrset_all_next;
289 if(msg->rrset_last == rrset)
290 msg->rrset_last = prev;
294 p = p->rrset_all_next;
296 /* remove from count */
297 switch(rrset->section) {
298 case LDNS_SECTION_ANSWER: msg->an_rrsets--; break;
299 case LDNS_SECTION_AUTHORITY: msg->ns_rrsets--; break;
300 case LDNS_SECTION_ADDITIONAL: msg->ar_rrsets--; break;
301 default: log_assert(0);
303 /* insert at end of list */
304 rrset->rrset_all_next = 0;
306 msg->rrset_last->rrset_all_next = rrset;
307 else msg->rrset_first = rrset;
308 msg->rrset_last = rrset;
309 /* up count of new section */
311 case LDNS_SECTION_AUTHORITY: msg->ns_rrsets++; break;
312 case LDNS_SECTION_ADDITIONAL: msg->ar_rrsets++; break;
313 default: log_assert(0);
315 rrset->section = section;
318 /** see if rrset of type RRSIG contains sig over given type */
320 rrset_has_sigover(sldns_buffer* pkt, struct rrset_parse* rrset, uint16_t type,
324 struct rr_parse* rr = rrset->rr_first;
325 log_assert( rrset->type == LDNS_RR_TYPE_RRSIG );
327 if(pkt_rrsig_covered_equals(pkt, rr->ttl_data, type))
335 /** move rrsigs from sigset to dataset */
337 moveover_rrsigs(sldns_buffer* pkt, struct regional* region,
338 struct rrset_parse* sigset, struct rrset_parse* dataset, int duplicate)
340 struct rr_parse* sig = sigset->rr_first;
341 struct rr_parse* prev = NULL;
342 struct rr_parse* insert;
343 struct rr_parse* nextsig;
346 if(pkt_rrsig_covered_equals(pkt, sig->ttl_data,
350 insert = (struct rr_parse*)regional_alloc(
351 region, sizeof(struct rr_parse));
352 if(!insert) return 0;
353 insert->outside_packet = 0;
354 insert->ttl_data = sig->ttl_data;
355 insert->size = sig->size;
358 /* remove from sigset */
359 if(prev) prev->next = sig->next;
360 else sigset->rr_first = sig->next;
361 if(sigset->rr_last == sig)
362 sigset->rr_last = prev;
364 sigset->size -= sig->size;
366 /* prev not changed */
369 dataset->rrsig_count++;
371 if(dataset->rrsig_last)
372 dataset->rrsig_last->next = insert;
373 else dataset->rrsig_first = insert;
374 dataset->rrsig_last = insert;
375 dataset->size += insert->size;
384 /** change an rrsig rrset for use as data rrset */
385 static struct rrset_parse*
386 change_rrsig_rrset(struct rrset_parse* sigset, struct msg_parse* msg,
387 sldns_buffer* pkt, uint16_t datatype, uint32_t rrset_flags,
388 int hasother, sldns_pkt_section section, struct regional* region)
390 struct rrset_parse* dataset = sigset;
391 hashvalue_type hash = pkt_hash_rrset(pkt, sigset->dname, datatype,
392 sigset->rrset_class, rrset_flags);
393 log_assert( sigset->type == LDNS_RR_TYPE_RRSIG );
394 log_assert( datatype != LDNS_RR_TYPE_RRSIG );
396 /* need to make new rrset to hold data type */
397 dataset = new_rrset(msg, sigset->dname, sigset->dname_len,
398 datatype, sigset->rrset_class, hash, rrset_flags,
403 case LDNS_SECTION_ANSWER: msg->an_rrsets++; break;
404 case LDNS_SECTION_AUTHORITY: msg->ns_rrsets++; break;
405 case LDNS_SECTION_ADDITIONAL: msg->ar_rrsets++; break;
406 default: log_assert(0);
408 if(!moveover_rrsigs(pkt, region, sigset, dataset,
409 msg->qtype == LDNS_RR_TYPE_RRSIG ||
410 (msg->qtype == LDNS_RR_TYPE_ANY &&
411 section != LDNS_SECTION_ANSWER) ))
415 /* changeover the type of the rrset to data set */
416 msgparse_bucket_remove(msg, dataset);
417 /* insert into new hash bucket */
418 dataset->rrset_bucket_next = msg->hashtable[hash&(PARSE_TABLE_SIZE-1)];
419 msg->hashtable[hash&(PARSE_TABLE_SIZE-1)] = dataset;
420 dataset->hash = hash;
421 /* use section of data item for result */
422 change_section(msg, dataset, section);
423 dataset->type = datatype;
424 dataset->flags = rrset_flags;
425 dataset->rrsig_count += dataset->rr_count;
426 dataset->rr_count = 0;
427 /* move sigs to end of siglist */
428 if(dataset->rrsig_last)
429 dataset->rrsig_last->next = dataset->rr_first;
430 else dataset->rrsig_first = dataset->rr_first;
431 dataset->rrsig_last = dataset->rr_last;
432 dataset->rr_first = 0;
433 dataset->rr_last = 0;
437 /** Find rrset. If equal to previous it is fast. hash if not so.
438 * @param msg: the message with hash table.
439 * @param pkt: the packet in wireformat (needed for compression ptrs).
440 * @param dname: pointer to start of dname (compressed) in packet.
441 * @param dnamelen: uncompressed wirefmt length of dname.
442 * @param type: type of current rr.
443 * @param dclass: class of current rr.
444 * @param hash: hash value is returned if the rrset could not be found.
445 * @param rrset_flags: is returned if the rrset could not be found.
446 * @param prev_dname_first: dname of last seen RR. First seen dname.
447 * @param prev_dname_last: dname of last seen RR. Last seen dname.
448 * @param prev_dnamelen: dname len of last seen RR.
449 * @param prev_type: type of last seen RR.
450 * @param prev_dclass: class of last seen RR.
451 * @param rrset_prev: last seen RRset.
452 * @param section: the current section in the packet.
453 * @param region: used to allocate temporary parsing data.
454 * @return 0 on out of memory.
457 find_rrset(struct msg_parse* msg, sldns_buffer* pkt, uint8_t* dname,
458 size_t dnamelen, uint16_t type, uint16_t dclass, hashvalue_type* hash,
459 uint32_t* rrset_flags,
460 uint8_t** prev_dname_first, uint8_t** prev_dname_last,
461 size_t* prev_dnamelen, uint16_t* prev_type,
462 uint16_t* prev_dclass, struct rrset_parse** rrset_prev,
463 sldns_pkt_section section, struct regional* region)
465 hashvalue_type dname_h = pkt_hash_rrset_first(pkt, dname);
468 /* check if equal to previous item */
469 if(type == *prev_type && dclass == *prev_dclass &&
470 dnamelen == *prev_dnamelen &&
471 smart_compare(pkt, dname, *prev_dname_first,
472 *prev_dname_last) == 0 &&
473 type != LDNS_RR_TYPE_RRSIG) {
474 /* same as previous */
475 *prev_dname_last = dname;
478 /* check if rrsig over previous item */
479 if(type == LDNS_RR_TYPE_RRSIG && dclass == *prev_dclass &&
480 pkt_rrsig_covered_equals(pkt, sldns_buffer_current(pkt),
482 smart_compare(pkt, dname, *prev_dname_first,
483 *prev_dname_last) == 0) {
484 /* covers previous */
485 *prev_dname_last = dname;
489 /* find by hashing and lookup in hashtable */
490 *rrset_flags = pkt_rrset_flags(pkt, type, section);
492 /* if rrsig - try to lookup matching data set first */
493 if(type == LDNS_RR_TYPE_RRSIG && pkt_rrsig_covered(pkt,
494 sldns_buffer_current(pkt), &covtype)) {
495 *hash = pkt_hash_rrset_rest(dname_h, covtype, dclass,
497 *rrset_prev = msgparse_hashtable_lookup(msg, pkt, *hash,
498 *rrset_flags, dname, dnamelen, covtype, dclass);
499 if(!*rrset_prev && covtype == LDNS_RR_TYPE_NSEC) {
500 /* if NSEC try with NSEC apex bit twiddled */
501 *rrset_flags ^= PACKED_RRSET_NSEC_AT_APEX;
502 *hash = pkt_hash_rrset_rest(dname_h, covtype, dclass,
504 *rrset_prev = msgparse_hashtable_lookup(msg, pkt,
505 *hash, *rrset_flags, dname, dnamelen, covtype,
507 if(!*rrset_prev) /* untwiddle if not found */
508 *rrset_flags ^= PACKED_RRSET_NSEC_AT_APEX;
510 if(!*rrset_prev && covtype == LDNS_RR_TYPE_SOA) {
511 /* if SOA try with SOA neg flag twiddled */
512 *rrset_flags ^= PACKED_RRSET_SOA_NEG;
513 *hash = pkt_hash_rrset_rest(dname_h, covtype, dclass,
515 *rrset_prev = msgparse_hashtable_lookup(msg, pkt,
516 *hash, *rrset_flags, dname, dnamelen, covtype,
518 if(!*rrset_prev) /* untwiddle if not found */
519 *rrset_flags ^= PACKED_RRSET_SOA_NEG;
522 *prev_dname_first = (*rrset_prev)->dname;
523 *prev_dname_last = dname;
524 *prev_dnamelen = dnamelen;
525 *prev_type = covtype;
526 *prev_dclass = dclass;
530 if(type != LDNS_RR_TYPE_RRSIG) {
532 /* find matching rrsig */
533 *hash = pkt_hash_rrset_rest(dname_h, LDNS_RR_TYPE_RRSIG,
535 *rrset_prev = msgparse_hashtable_lookup(msg, pkt, *hash,
536 0, dname, dnamelen, LDNS_RR_TYPE_RRSIG,
538 if(*rrset_prev && rrset_has_sigover(pkt, *rrset_prev, type,
541 *prev_dname_first = (*rrset_prev)->dname;
542 *prev_dname_last = dname;
543 *prev_dnamelen = dnamelen;
545 *prev_dclass = dclass;
546 *rrset_prev = change_rrsig_rrset(*rrset_prev, msg,
547 pkt, type, *rrset_flags, hasother, section,
549 if(!*rrset_prev) return 0;
554 *hash = pkt_hash_rrset_rest(dname_h, type, dclass, *rrset_flags);
555 *rrset_prev = msgparse_hashtable_lookup(msg, pkt, *hash, *rrset_flags,
556 dname, dnamelen, type, dclass);
558 *prev_dname_first = (*rrset_prev)->dname;
559 else *prev_dname_first = dname;
560 *prev_dname_last = dname;
561 *prev_dnamelen = dnamelen;
563 *prev_dclass = dclass;
568 * Parse query section.
569 * @param pkt: packet, position at call must be at start of query section.
570 * at end position is after query section.
571 * @param msg: store results here.
572 * @return: 0 if OK, or rcode on error.
575 parse_query_section(sldns_buffer* pkt, struct msg_parse* msg)
577 if(msg->qdcount == 0)
580 return LDNS_RCODE_FORMERR;
581 log_assert(msg->qdcount == 1);
582 if(sldns_buffer_remaining(pkt) <= 0)
583 return LDNS_RCODE_FORMERR;
584 msg->qname = sldns_buffer_current(pkt);
585 if((msg->qname_len = pkt_dname_len(pkt)) == 0)
586 return LDNS_RCODE_FORMERR;
587 if(sldns_buffer_remaining(pkt) < sizeof(uint16_t)*2)
588 return LDNS_RCODE_FORMERR;
589 msg->qtype = sldns_buffer_read_u16(pkt);
590 msg->qclass = sldns_buffer_read_u16(pkt);
595 get_rdf_size(sldns_rdf_type rdf)
598 case LDNS_RDF_TYPE_CLASS:
599 case LDNS_RDF_TYPE_ALG:
600 case LDNS_RDF_TYPE_INT8:
603 case LDNS_RDF_TYPE_INT16:
604 case LDNS_RDF_TYPE_TYPE:
605 case LDNS_RDF_TYPE_CERT_ALG:
608 case LDNS_RDF_TYPE_INT32:
609 case LDNS_RDF_TYPE_TIME:
610 case LDNS_RDF_TYPE_A:
611 case LDNS_RDF_TYPE_PERIOD:
614 case LDNS_RDF_TYPE_TSIGTIME:
617 case LDNS_RDF_TYPE_AAAA:
621 log_assert(0); /* add type above */
622 /* only types that appear before a domain *
623 * name are needed. rest is simply copied. */
628 /** calculate the size of one rr */
630 calc_size(sldns_buffer* pkt, uint16_t type, struct rr_parse* rr)
632 const sldns_rr_descriptor* desc;
633 uint16_t pkt_len; /* length of rr inside the packet */
634 rr->size = sizeof(uint16_t); /* the rdatalen */
635 sldns_buffer_skip(pkt, 4); /* skip ttl */
636 pkt_len = sldns_buffer_read_u16(pkt);
637 if(sldns_buffer_remaining(pkt) < pkt_len)
639 desc = sldns_rr_descript(type);
640 if(pkt_len > 0 && desc && desc->_dname_count > 0) {
641 int count = (int)desc->_dname_count;
645 /* skip first part. */
646 while(pkt_len > 0 && count) {
647 switch(desc->_wireformat[rdf]) {
648 case LDNS_RDF_TYPE_DNAME:
649 /* decompress every domain name */
650 oldpos = sldns_buffer_position(pkt);
651 if((len = pkt_dname_len(pkt)) == 0)
652 return 0; /* malformed dname */
653 if(sldns_buffer_position(pkt)-oldpos > pkt_len)
654 return 0; /* dname exceeds rdata */
655 pkt_len -= sldns_buffer_position(pkt)-oldpos;
660 case LDNS_RDF_TYPE_STR:
662 /* NOTREACHED, due to 'while(>0)' */
663 return 0; /* len byte exceeds rdata */
665 len = sldns_buffer_current(pkt)[0] + 1;
668 len = get_rdf_size(desc->_wireformat[rdf]);
672 return 0; /* exceeds rdata */
674 sldns_buffer_skip(pkt, (ssize_t)len);
680 /* remaining rdata */
682 sldns_buffer_skip(pkt, (ssize_t)pkt_len);
686 /** skip rr ttl and rdata */
688 skip_ttl_rdata(sldns_buffer* pkt)
691 if(sldns_buffer_remaining(pkt) < 6) /* ttl + rdatalen */
693 sldns_buffer_skip(pkt, 4); /* ttl */
694 rdatalen = sldns_buffer_read_u16(pkt);
695 if(sldns_buffer_remaining(pkt) < rdatalen)
697 sldns_buffer_skip(pkt, (ssize_t)rdatalen);
701 /** see if RRSIG is a duplicate of another */
703 sig_is_double(sldns_buffer* pkt, struct rrset_parse* rrset, uint8_t* ttldata)
705 uint16_t rlen, siglen;
706 size_t pos = sldns_buffer_position(pkt);
707 struct rr_parse* sig;
708 if(sldns_buffer_remaining(pkt) < 6)
710 sldns_buffer_skip(pkt, 4); /* ttl */
711 rlen = sldns_buffer_read_u16(pkt);
712 if(sldns_buffer_remaining(pkt) < rlen) {
713 sldns_buffer_set_position(pkt, pos);
716 sldns_buffer_set_position(pkt, pos);
718 sig = rrset->rrsig_first;
720 /* check if rdatalen is same */
721 memmove(&siglen, sig->ttl_data+4, sizeof(siglen));
722 siglen = ntohs(siglen);
723 /* checks if data in packet is exactly the same, this means
724 * also dname in rdata is the same, but rrsig is not allowed
725 * to have compressed dnames anyway. If it is compressed anyway
726 * it will lead to duplicate rrs for qtype=RRSIG. (or ANY).
728 * Cannot use sig->size because size of the other one is not
732 if(siglen>0 && memcmp(sig->ttl_data+6, ttldata+6,
743 /** Add rr (from packet here) to rrset, skips rr */
745 add_rr_to_rrset(struct rrset_parse* rrset, sldns_buffer* pkt,
746 struct msg_parse* msg, struct regional* region,
747 sldns_pkt_section section, uint16_t type)
750 /* check section of rrset. */
751 if(rrset->section != section && type != LDNS_RR_TYPE_RRSIG &&
752 rrset->type != LDNS_RR_TYPE_RRSIG) {
753 /* silently drop it - we drop the last part, since
754 * trust in rr data depends on the section it is in.
755 * the less trustworthy part is discarded.
756 * also the last part is more likely to be incomplete.
757 * RFC 2181: must put RRset only once in response. */
759 verbose(VERB_QUERY, "Packet contains rrset data in "
760 "multiple sections, dropped last part.");
761 log_buf(VERB_QUERY, "packet was", pkt);
764 if(!skip_ttl_rdata(pkt))
765 return LDNS_RCODE_FORMERR;
769 if( (msg->qtype == LDNS_RR_TYPE_RRSIG ||
770 msg->qtype == LDNS_RR_TYPE_ANY)
771 && sig_is_double(pkt, rrset, sldns_buffer_current(pkt))) {
772 if(!skip_ttl_rdata(pkt))
773 return LDNS_RCODE_FORMERR;
778 if(!(rr = (struct rr_parse*)regional_alloc(region, sizeof(*rr))))
779 return LDNS_RCODE_SERVFAIL;
780 rr->outside_packet = 0;
781 rr->ttl_data = sldns_buffer_current(pkt);
783 if(type == LDNS_RR_TYPE_RRSIG && rrset->type != LDNS_RR_TYPE_RRSIG) {
784 if(rrset->rrsig_last)
785 rrset->rrsig_last->next = rr;
786 else rrset->rrsig_first = rr;
787 rrset->rrsig_last = rr;
788 rrset->rrsig_count++;
791 rrset->rr_last->next = rr;
792 else rrset->rr_first = rr;
797 /* calc decompressed size */
798 if(!calc_size(pkt, type, rr))
799 return LDNS_RCODE_FORMERR;
800 rrset->size += rr->size;
806 * Parse packet RR section, for answer, authority and additional sections.
807 * @param pkt: packet, position at call must be at start of section.
808 * at end position is after section.
809 * @param msg: store results here.
810 * @param region: how to alloc results.
811 * @param section: section enum.
812 * @param num_rrs: how many rrs are in the section.
813 * @param num_rrsets: returns number of rrsets in the section.
814 * @return: 0 if OK, or rcode on error.
817 parse_section(sldns_buffer* pkt, struct msg_parse* msg,
818 struct regional* region, sldns_pkt_section section,
819 uint16_t num_rrs, size_t* num_rrsets)
822 uint8_t* dname, *prev_dname_f = NULL, *prev_dname_l = NULL;
823 size_t dnamelen, prev_dnamelen = 0;
824 uint16_t type, prev_type = 0;
825 uint16_t dclass, prev_dclass = 0;
826 uint32_t rrset_flags = 0;
827 hashvalue_type hash = 0;
828 struct rrset_parse* rrset = NULL;
833 if(sldns_buffer_remaining(pkt) <= 0)
834 return LDNS_RCODE_FORMERR;
835 for(i=0; i<num_rrs; i++) {
837 dname = sldns_buffer_current(pkt);
838 if((dnamelen = pkt_dname_len(pkt)) == 0)
839 return LDNS_RCODE_FORMERR;
840 if(sldns_buffer_remaining(pkt) < 10) /* type, class, ttl, len */
841 return LDNS_RCODE_FORMERR;
842 type = sldns_buffer_read_u16(pkt);
843 sldns_buffer_read(pkt, &dclass, sizeof(dclass));
845 if(0) { /* debug show what is being parsed. */
846 if(type == LDNS_RR_TYPE_RRSIG) {
848 if(pkt_rrsig_covered(pkt,
849 sldns_buffer_current(pkt), &t))
850 fprintf(stderr, "parse of %s(%d) [%s(%d)]",
851 sldns_rr_descript(type)?
852 sldns_rr_descript(type)->_name: "??",
854 sldns_rr_descript(t)?
855 sldns_rr_descript(t)->_name: "??",
858 fprintf(stderr, "parse of %s(%d)",
859 sldns_rr_descript(type)?
860 sldns_rr_descript(type)->_name: "??",
862 fprintf(stderr, " %s(%d) ",
863 sldns_lookup_by_id(sldns_rr_classes,
864 (int)ntohs(dclass))?sldns_lookup_by_id(
865 sldns_rr_classes, (int)ntohs(dclass))->name:
866 "??", (int)ntohs(dclass));
867 dname_print(stderr, pkt, dname);
868 fprintf(stderr, "\n");
871 /* see if it is part of an existing RR set */
872 if(!find_rrset(msg, pkt, dname, dnamelen, type, dclass, &hash,
873 &rrset_flags, &prev_dname_f, &prev_dname_l,
874 &prev_dnamelen, &prev_type, &prev_dclass, &rrset,
876 return LDNS_RCODE_SERVFAIL;
878 /* it is a new RR set. hash&flags already calculated.*/
880 rrset = new_rrset(msg, dname, dnamelen, type, dclass,
881 hash, rrset_flags, section, region);
883 return LDNS_RCODE_SERVFAIL;
886 fprintf(stderr, "is part of existing: ");
887 dname_print(stderr, pkt, rrset->dname);
888 fprintf(stderr, " type %s(%d)\n",
889 sldns_rr_descript(rrset->type)?
890 sldns_rr_descript(rrset->type)->_name: "??",
894 if((r=add_rr_to_rrset(rrset, pkt, msg, region, section,
902 parse_packet(sldns_buffer* pkt, struct msg_parse* msg, struct regional* region)
905 if(sldns_buffer_remaining(pkt) < LDNS_HEADER_SIZE)
906 return LDNS_RCODE_FORMERR;
907 /* read the header */
908 sldns_buffer_read(pkt, &msg->id, sizeof(uint16_t));
909 msg->flags = sldns_buffer_read_u16(pkt);
910 msg->qdcount = sldns_buffer_read_u16(pkt);
911 msg->ancount = sldns_buffer_read_u16(pkt);
912 msg->nscount = sldns_buffer_read_u16(pkt);
913 msg->arcount = sldns_buffer_read_u16(pkt);
915 return LDNS_RCODE_FORMERR;
916 if((ret = parse_query_section(pkt, msg)) != 0)
918 if((ret = parse_section(pkt, msg, region, LDNS_SECTION_ANSWER,
919 msg->ancount, &msg->an_rrsets)) != 0)
921 if((ret = parse_section(pkt, msg, region, LDNS_SECTION_AUTHORITY,
922 msg->nscount, &msg->ns_rrsets)) != 0)
924 if(sldns_buffer_remaining(pkt) == 0 && msg->arcount == 1) {
925 /* BIND accepts leniently that an EDNS record is missing.
927 } else if((ret = parse_section(pkt, msg, region,
928 LDNS_SECTION_ADDITIONAL, msg->arcount, &msg->ar_rrsets)) != 0)
930 /* if(sldns_buffer_remaining(pkt) > 0) { */
931 /* there is spurious data at end of packet. ignore */
933 msg->rrset_count = msg->an_rrsets + msg->ns_rrsets + msg->ar_rrsets;
937 /** parse EDNS options from EDNS wireformat rdata */
939 parse_edns_options(uint8_t* rdata_ptr, size_t rdata_len,
940 struct edns_data* edns, struct regional* region)
942 /* while still more options, and have code+len to read */
943 /* ignores partial content (i.e. rdata len 3) */
944 while(rdata_len >= 4) {
945 uint16_t opt_code = sldns_read_uint16(rdata_ptr);
946 uint16_t opt_len = sldns_read_uint16(rdata_ptr+2);
949 if(opt_len > rdata_len)
950 break; /* option code partial */
951 if(!edns_opt_append(edns, region, opt_code, opt_len,
953 log_err("out of memory");
956 rdata_ptr += opt_len;
957 rdata_len -= opt_len;
963 parse_extract_edns(struct msg_parse* msg, struct edns_data* edns,
964 struct regional* region)
966 struct rrset_parse* rrset = msg->rrset_first;
967 struct rrset_parse* prev = 0;
968 struct rrset_parse* found = 0;
969 struct rrset_parse* found_prev = 0;
972 /* since the class encodes the UDP size, we cannot use hash table to
973 * find the EDNS OPT record. Scan the packet. */
975 if(rrset->type == LDNS_RR_TYPE_OPT) {
976 /* only one OPT RR allowed. */
977 if(found) return LDNS_RCODE_FORMERR;
983 rrset = rrset->rrset_all_next;
986 memset(edns, 0, sizeof(*edns));
987 edns->udp_size = 512;
990 /* check the found RRset */
991 /* most lenient check possible. ignore dname, use last opt */
992 if(found->section != LDNS_SECTION_ADDITIONAL)
993 return LDNS_RCODE_FORMERR;
994 if(found->rr_count == 0)
995 return LDNS_RCODE_FORMERR;
996 if(0) { /* strict checking of dname and RRcount */
997 if(found->dname_len != 1 || !found->dname
998 || found->dname[0] != 0) return LDNS_RCODE_FORMERR;
999 if(found->rr_count != 1) return LDNS_RCODE_FORMERR;
1001 log_assert(found->rr_first && found->rr_last);
1003 /* remove from packet */
1004 if(found_prev) found_prev->rrset_all_next = found->rrset_all_next;
1005 else msg->rrset_first = found->rrset_all_next;
1006 if(found == msg->rrset_last)
1007 msg->rrset_last = found_prev;
1010 msg->rrset_count --;
1012 /* take the data ! */
1013 edns->edns_present = 1;
1014 edns->ext_rcode = found->rr_last->ttl_data[0];
1015 edns->edns_version = found->rr_last->ttl_data[1];
1016 edns->bits = sldns_read_uint16(&found->rr_last->ttl_data[2]);
1017 edns->udp_size = ntohs(found->rrset_class);
1018 edns->opt_list = NULL;
1020 /* take the options */
1021 rdata_len = found->rr_first->size;
1022 rdata_ptr = found->rr_first->ttl_data+6;
1023 if(!parse_edns_options(rdata_ptr, rdata_len, edns, region))
1032 parse_edns_from_pkt(sldns_buffer* pkt, struct edns_data* edns,
1033 struct regional* region)
1037 log_assert(LDNS_QDCOUNT(sldns_buffer_begin(pkt)) == 1);
1038 log_assert(LDNS_ANCOUNT(sldns_buffer_begin(pkt)) == 0);
1039 log_assert(LDNS_NSCOUNT(sldns_buffer_begin(pkt)) == 0);
1040 /* check edns section is present */
1041 if(LDNS_ARCOUNT(sldns_buffer_begin(pkt)) > 1) {
1042 return LDNS_RCODE_FORMERR;
1044 if(LDNS_ARCOUNT(sldns_buffer_begin(pkt)) == 0) {
1045 memset(edns, 0, sizeof(*edns));
1046 edns->udp_size = 512;
1049 /* domain name must be the root of length 1. */
1050 if(pkt_dname_len(pkt) != 1)
1051 return LDNS_RCODE_FORMERR;
1052 if(sldns_buffer_remaining(pkt) < 10) /* type, class, ttl, rdatalen */
1053 return LDNS_RCODE_FORMERR;
1054 if(sldns_buffer_read_u16(pkt) != LDNS_RR_TYPE_OPT)
1055 return LDNS_RCODE_FORMERR;
1056 edns->edns_present = 1;
1057 edns->udp_size = sldns_buffer_read_u16(pkt); /* class is udp size */
1058 edns->ext_rcode = sldns_buffer_read_u8(pkt); /* ttl used for bits */
1059 edns->edns_version = sldns_buffer_read_u8(pkt);
1060 edns->bits = sldns_buffer_read_u16(pkt);
1061 edns->opt_list = NULL;
1063 /* take the options */
1064 rdata_len = sldns_buffer_read_u16(pkt);
1065 if(sldns_buffer_remaining(pkt) < rdata_len)
1066 return LDNS_RCODE_FORMERR;
1067 rdata_ptr = sldns_buffer_current(pkt);
1068 if(!parse_edns_options(rdata_ptr, rdata_len, edns, region))
1069 return LDNS_RCODE_SERVFAIL;
1077 log_edns_opt_list(enum verbosity_value level, const char* info_str,
1078 struct edns_option* list)
1080 if(verbosity >= level && list) {
1083 verbose(level, "%s", info_str);
1087 (void)sldns_wire2str_edns_option_print(&s, &slen, list->opt_code,
1088 list->opt_data, list->opt_len);
1089 verbose(level, " %s", str);