2 * util/data/msgencode.c - Encode DNS messages, queries and replies.
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.
39 * This file contains a routines to encode DNS messages.
43 #include "util/data/msgencode.h"
44 #include "util/data/msgreply.h"
45 #include "util/data/msgparse.h"
46 #include "util/data/dname.h"
48 #include "util/regional.h"
49 #include "util/net_help.h"
50 #include "sldns/sbuffer.h"
51 #include "services/localzone.h"
53 /** return code that means the function ran out of memory. negative so it does
54 * not conflict with DNS rcodes. */
55 #define RETVAL_OUTMEM -2
56 /** return code that means the data did not fit (completely) in the packet */
57 #define RETVAL_TRUNC -4
58 /** return code that means all is peachy keen. Equal to DNS rcode NOERROR */
62 * Data structure to help domain name compression in outgoing messages.
63 * A tree of dnames and their offsets in the packet is kept.
64 * It is kept sorted, not canonical, but by label at least, so that after
65 * a lookup of a name you know its closest match, and the parent from that
66 * closest match. These are possible compression targets.
68 * It is a binary tree, not a rbtree or balanced tree, as the effort
69 * of keeping it balanced probably outweighs usefulness (given typical
72 struct compress_tree_node {
73 /** left node in tree, all smaller to this */
74 struct compress_tree_node* left;
75 /** right node in tree, all larger than this */
76 struct compress_tree_node* right;
78 /** the parent node - not for tree, but zone parent. One less label */
79 struct compress_tree_node* parent;
80 /** the domain name for this node. Pointer to uncompressed memory. */
82 /** number of labels in domain name, kept to help compare func. */
84 /** offset in packet that points to this dname */
89 * Find domain name in tree, returns exact and closest match.
90 * @param tree: root of tree.
91 * @param dname: pointer to uncompressed dname.
92 * @param labs: number of labels in domain name.
93 * @param match: closest or exact match.
94 * guaranteed to be smaller or equal to the sought dname.
95 * can be null if the tree is empty.
96 * @param matchlabels: number of labels that match with closest match.
97 * can be zero is there is no match.
98 * @param insertpt: insert location for dname, if not found.
99 * @return: 0 if no exact match.
102 compress_tree_search(struct compress_tree_node** tree, uint8_t* dname,
103 int labs, struct compress_tree_node** match, int* matchlabels,
104 struct compress_tree_node*** insertpt)
107 struct compress_tree_node* p = *tree;
108 struct compress_tree_node* close = 0;
109 struct compress_tree_node** prev = tree;
111 if((c = dname_lab_cmp(dname, labs, p->dname, p->labs, &n))
122 close = p; /* p->dname is smaller than dname */
128 *matchlabels = closen;
134 * Lookup a domain name in compression tree.
135 * @param tree: root of tree (not the node with '.').
136 * @param dname: pointer to uncompressed dname.
137 * @param labs: number of labels in domain name.
138 * @param insertpt: insert location for dname, if not found.
139 * @return: 0 if not found or compress treenode with best compression.
141 static struct compress_tree_node*
142 compress_tree_lookup(struct compress_tree_node** tree, uint8_t* dname,
143 int labs, struct compress_tree_node*** insertpt)
145 struct compress_tree_node* p;
148 return 0; /* do not compress root node */
149 if(compress_tree_search(tree, dname, labs, &p, &m, insertpt)) {
153 /* return some ancestor of p that compresses well. */
155 /* www.example.com. (labs=4) matched foo.example.com.(labs=4)
156 * then matchcount = 3. need to go up. */
157 while(p && p->labs > m)
165 * Create node for domain name compression tree.
166 * @param dname: pointer to uncompressed dname (stored in tree).
167 * @param labs: number of labels in dname.
168 * @param offset: offset into packet for dname.
169 * @param region: how to allocate memory for new node.
170 * @return new node or 0 on malloc failure.
172 static struct compress_tree_node*
173 compress_tree_newnode(uint8_t* dname, int labs, size_t offset,
174 struct regional* region)
176 struct compress_tree_node* n = (struct compress_tree_node*)
177 regional_alloc(region, sizeof(struct compress_tree_node));
189 * Store domain name and ancestors into compression tree.
190 * @param dname: pointer to uncompressed dname (stored in tree).
191 * @param labs: number of labels in dname.
192 * @param offset: offset into packet for dname.
193 * @param region: how to allocate memory for new node.
194 * @param closest: match from previous lookup, used to compress dname.
195 * may be NULL if no previous match.
196 * if the tree has an ancestor of dname already, this must be it.
197 * @param insertpt: where to insert the dname in tree.
198 * @return: 0 on memory error.
201 compress_tree_store(uint8_t* dname, int labs, size_t offset,
202 struct regional* region, struct compress_tree_node* closest,
203 struct compress_tree_node** insertpt)
206 struct compress_tree_node* newnode;
207 struct compress_tree_node* prevnode = NULL;
208 int uplabs = labs-1; /* does not store root in tree */
209 if(closest) uplabs = labs - closest->labs;
210 log_assert(uplabs >= 0);
211 /* algorithms builds up a vine of dname-labels to hang into tree */
213 if(offset > PTR_MAX_OFFSET) {
214 /* insertion failed, drop vine */
215 return 1; /* compression pointer no longer useful */
217 if(!(newnode = compress_tree_newnode(dname, labs, offset,
219 /* insertion failed, drop vine */
224 /* chain nodes together, last one has one label more,
225 * so is larger than newnode, thus goes right. */
226 newnode->right = prevnode;
227 prevnode->parent = newnode;
237 /* if we have a vine, hang the vine into the tree */
239 *insertpt = prevnode;
240 prevnode->parent = closest;
245 /** compress a domain name */
247 write_compressed_dname(sldns_buffer* pkt, uint8_t* dname, int labs,
248 struct compress_tree_node* p)
251 int labcopy = labs - p->labs;
256 /* write root label */
257 if(sldns_buffer_remaining(pkt) < 1)
259 sldns_buffer_write_u8(pkt, 0);
263 /* copy the first couple of labels */
266 if(sldns_buffer_remaining(pkt) < (size_t)lablen+1)
268 sldns_buffer_write_u8(pkt, lablen);
269 sldns_buffer_write(pkt, dname, lablen);
272 /* insert compression ptr */
273 if(sldns_buffer_remaining(pkt) < 2)
275 ptr = PTR_CREATE(p->offset);
276 sldns_buffer_write_u16(pkt, ptr);
280 /** compress owner name of RR, return RETVAL_OUTMEM RETVAL_TRUNC */
282 compress_owner(struct ub_packed_rrset_key* key, sldns_buffer* pkt,
283 struct regional* region, struct compress_tree_node** tree,
284 size_t owner_pos, uint16_t* owner_ptr, int owner_labs)
286 struct compress_tree_node* p;
287 struct compress_tree_node** insertpt = NULL;
289 /* compress first time dname */
290 if((p = compress_tree_lookup(tree, key->rk.dname,
291 owner_labs, &insertpt))) {
292 if(p->labs == owner_labs)
293 /* avoid ptr chains, since some software is
294 * not capable of decoding ptr after a ptr. */
295 *owner_ptr = htons(PTR_CREATE(p->offset));
296 if(!write_compressed_dname(pkt, key->rk.dname,
299 /* check if typeclass+4 ttl + rdatalen is available */
300 if(sldns_buffer_remaining(pkt) < 4+4+2)
304 if(sldns_buffer_remaining(pkt) < key->rk.dname_len+4+4+2)
306 sldns_buffer_write(pkt, key->rk.dname,
308 if(owner_pos <= PTR_MAX_OFFSET)
309 *owner_ptr = htons(PTR_CREATE(owner_pos));
311 if(!compress_tree_store(key->rk.dname, owner_labs,
312 owner_pos, region, p, insertpt))
313 return RETVAL_OUTMEM;
315 /* always compress 2nd-further RRs in RRset */
316 if(owner_labs == 1) {
317 if(sldns_buffer_remaining(pkt) < 1+4+4+2)
319 sldns_buffer_write_u8(pkt, 0);
321 if(sldns_buffer_remaining(pkt) < 2+4+4+2)
323 sldns_buffer_write(pkt, owner_ptr, 2);
329 /** compress any domain name to the packet, return RETVAL_* */
331 compress_any_dname(uint8_t* dname, sldns_buffer* pkt, int labs,
332 struct regional* region, struct compress_tree_node** tree)
334 struct compress_tree_node* p;
335 struct compress_tree_node** insertpt = NULL;
336 size_t pos = sldns_buffer_position(pkt);
337 if((p = compress_tree_lookup(tree, dname, labs, &insertpt))) {
338 if(!write_compressed_dname(pkt, dname, labs, p))
341 if(!dname_buffer_write(pkt, dname))
344 if(!compress_tree_store(dname, labs, pos, region, p, insertpt))
345 return RETVAL_OUTMEM;
349 /** return true if type needs domain name compression in rdata */
350 static const sldns_rr_descriptor*
351 type_rdata_compressable(struct ub_packed_rrset_key* key)
353 uint16_t t = ntohs(key->rk.type);
354 if(sldns_rr_descript(t) &&
355 sldns_rr_descript(t)->_compress == LDNS_RR_COMPRESS)
356 return sldns_rr_descript(t);
360 /** compress domain names in rdata, return RETVAL_* */
362 compress_rdata(sldns_buffer* pkt, uint8_t* rdata, size_t todolen,
363 struct regional* region, struct compress_tree_node** tree,
364 const sldns_rr_descriptor* desc)
366 int labs, r, rdf = 0;
367 size_t dname_len, len, pos = sldns_buffer_position(pkt);
368 uint8_t count = desc->_dname_count;
370 sldns_buffer_skip(pkt, 2); /* rdata len fill in later */
371 /* space for rdatalen checked for already */
374 while(todolen > 0 && count) {
375 switch(desc->_wireformat[rdf]) {
376 case LDNS_RDF_TYPE_DNAME:
377 labs = dname_count_size_labels(rdata, &dname_len);
378 if((r=compress_any_dname(rdata, pkt, labs, region,
382 todolen -= dname_len;
386 case LDNS_RDF_TYPE_STR:
390 len = get_rdf_size(desc->_wireformat[rdf]);
394 if(sldns_buffer_remaining(pkt) < len)
396 sldns_buffer_write(pkt, rdata, len);
404 if(sldns_buffer_remaining(pkt) < todolen)
406 sldns_buffer_write(pkt, rdata, todolen);
410 sldns_buffer_write_u16_at(pkt, pos, sldns_buffer_position(pkt)-pos-2);
414 /** Returns true if RR type should be included */
416 rrset_belongs_in_reply(sldns_pkt_section s, uint16_t rrtype, uint16_t qtype,
421 /* skip non DNSSEC types, except if directly queried for */
422 if(s == LDNS_SECTION_ANSWER) {
423 if(qtype == LDNS_RR_TYPE_ANY || qtype == rrtype)
426 /* check DNSSEC-ness */
428 case LDNS_RR_TYPE_SIG:
429 case LDNS_RR_TYPE_KEY:
430 case LDNS_RR_TYPE_NXT:
431 case LDNS_RR_TYPE_DS:
432 case LDNS_RR_TYPE_RRSIG:
433 case LDNS_RR_TYPE_NSEC:
434 case LDNS_RR_TYPE_DNSKEY:
435 case LDNS_RR_TYPE_NSEC3:
436 case LDNS_RR_TYPE_NSEC3PARAMS:
442 /** store rrset in buffer in wireformat, return RETVAL_* */
444 packed_rrset_encode(struct ub_packed_rrset_key* key, sldns_buffer* pkt,
445 uint16_t* num_rrs, time_t timenow, struct regional* region,
446 int do_data, int do_sig, struct compress_tree_node** tree,
447 sldns_pkt_section s, uint16_t qtype, int dnssec, size_t rr_offset)
449 size_t i, j, owner_pos;
451 uint16_t owner_ptr = 0;
452 struct packed_rrset_data* data = (struct packed_rrset_data*)
455 /* does this RR type belong in the answer? */
456 if(!rrset_belongs_in_reply(s, ntohs(key->rk.type), qtype, dnssec))
459 owner_labs = dname_count_labels(key->rk.dname);
460 owner_pos = sldns_buffer_position(pkt);
462 /* For an rrset with a fixed TTL, use the rrset's TTL as given */
463 if((key->rk.flags & PACKED_RRSET_FIXEDTTL) != 0)
467 const sldns_rr_descriptor* c = type_rdata_compressable(key);
468 for(i=0; i<data->count; i++) {
469 /* rrset roundrobin */
470 j = (i + rr_offset) % data->count;
471 if((r=compress_owner(key, pkt, region, tree,
472 owner_pos, &owner_ptr, owner_labs))
475 sldns_buffer_write(pkt, &key->rk.type, 2);
476 sldns_buffer_write(pkt, &key->rk.rrset_class, 2);
477 if(data->rr_ttl[j] < timenow)
478 sldns_buffer_write_u32(pkt, 0);
479 else sldns_buffer_write_u32(pkt,
480 data->rr_ttl[j]-timenow);
482 if((r=compress_rdata(pkt, data->rr_data[j],
483 data->rr_len[j], region, tree, c))
487 if(sldns_buffer_remaining(pkt) < data->rr_len[j])
489 sldns_buffer_write(pkt, data->rr_data[j],
495 if(do_sig && dnssec) {
496 size_t total = data->count+data->rrsig_count;
497 for(i=data->count; i<total; i++) {
498 if(owner_ptr && owner_labs != 1) {
499 if(sldns_buffer_remaining(pkt) <
500 2+4+4+data->rr_len[i])
502 sldns_buffer_write(pkt, &owner_ptr, 2);
504 if((r=compress_any_dname(key->rk.dname,
505 pkt, owner_labs, region, tree))
508 if(sldns_buffer_remaining(pkt) <
512 sldns_buffer_write_u16(pkt, LDNS_RR_TYPE_RRSIG);
513 sldns_buffer_write(pkt, &key->rk.rrset_class, 2);
514 if(data->rr_ttl[i] < timenow)
515 sldns_buffer_write_u32(pkt, 0);
516 else sldns_buffer_write_u32(pkt,
517 data->rr_ttl[i]-timenow);
518 /* rrsig rdata cannot be compressed, perform 100+ byte
520 sldns_buffer_write(pkt, data->rr_data[i],
524 /* change rrnum only after we are sure it fits */
526 *num_rrs += data->count;
528 *num_rrs += data->rrsig_count;
533 /** store msg section in wireformat buffer, return RETVAL_* */
535 insert_section(struct reply_info* rep, size_t num_rrsets, uint16_t* num_rrs,
536 sldns_buffer* pkt, size_t rrsets_before, time_t timenow,
537 struct regional* region, struct compress_tree_node** tree,
538 sldns_pkt_section s, uint16_t qtype, int dnssec, size_t rr_offset)
542 /* we now allow this function to be called multiple times for the
543 * same section, incrementally updating num_rrs. The caller is
544 * responsible for initializing it (which is the case in the current
545 * implementation). */
547 if(s != LDNS_SECTION_ADDITIONAL) {
548 if(s == LDNS_SECTION_ANSWER && qtype == LDNS_RR_TYPE_ANY)
549 dnssec = 1; /* include all types in ANY answer */
550 for(i=0; i<num_rrsets; i++) {
551 setstart = sldns_buffer_position(pkt);
552 if((r=packed_rrset_encode(rep->rrsets[rrsets_before+i],
553 pkt, num_rrs, timenow, region, 1, 1, tree,
554 s, qtype, dnssec, rr_offset))
556 /* Bad, but if due to size must set TC bit */
557 /* trim off the rrset neatly. */
558 sldns_buffer_set_position(pkt, setstart);
563 for(i=0; i<num_rrsets; i++) {
564 setstart = sldns_buffer_position(pkt);
565 if((r=packed_rrset_encode(rep->rrsets[rrsets_before+i],
566 pkt, num_rrs, timenow, region, 1, 0, tree,
567 s, qtype, dnssec, rr_offset))
569 sldns_buffer_set_position(pkt, setstart);
574 for(i=0; i<num_rrsets; i++) {
575 setstart = sldns_buffer_position(pkt);
576 if((r=packed_rrset_encode(rep->rrsets[rrsets_before+i],
577 pkt, num_rrs, timenow, region, 0, 1, tree,
578 s, qtype, dnssec, rr_offset))
580 sldns_buffer_set_position(pkt, setstart);
588 /** store query section in wireformat buffer, return RETVAL */
590 insert_query(struct query_info* qinfo, struct compress_tree_node** tree,
591 sldns_buffer* buffer, struct regional* region)
593 uint8_t* qname = qinfo->local_alias ?
594 qinfo->local_alias->rrset->rk.dname : qinfo->qname;
595 size_t qname_len = qinfo->local_alias ?
596 qinfo->local_alias->rrset->rk.dname_len : qinfo->qname_len;
597 if(sldns_buffer_remaining(buffer) <
598 qinfo->qname_len+sizeof(uint16_t)*2)
599 return RETVAL_TRUNC; /* buffer too small */
600 /* the query is the first name inserted into the tree */
601 if(!compress_tree_store(qname, dname_count_labels(qname),
602 sldns_buffer_position(buffer), region, NULL, tree))
603 return RETVAL_OUTMEM;
604 if(sldns_buffer_current(buffer) == qname)
605 sldns_buffer_skip(buffer, (ssize_t)qname_len);
606 else sldns_buffer_write(buffer, qname, qname_len);
607 sldns_buffer_write_u16(buffer, qinfo->qtype);
608 sldns_buffer_write_u16(buffer, qinfo->qclass);
613 positive_answer(struct reply_info* rep, uint16_t qtype) {
615 if (FLAGS_GET_RCODE(rep->flags) != LDNS_RCODE_NOERROR)
618 for(i=0;i<rep->an_numrrsets; i++) {
619 if(ntohs(rep->rrsets[i]->rk.type) == qtype) {
620 /* in case it is a wildcard with DNSSEC, there will
621 * be NSEC/NSEC3 records in the authority section
622 * that we cannot remove */
623 for(i=rep->an_numrrsets; i<rep->an_numrrsets+
624 rep->ns_numrrsets; i++) {
625 if(ntohs(rep->rrsets[i]->rk.type) ==
627 ntohs(rep->rrsets[i]->rk.type) ==
638 reply_info_encode(struct query_info* qinfo, struct reply_info* rep,
639 uint16_t id, uint16_t flags, sldns_buffer* buffer, time_t timenow,
640 struct regional* region, uint16_t udpsize, int dnssec)
642 uint16_t ancount=0, nscount=0, arcount=0;
643 struct compress_tree_node* tree = 0;
647 sldns_buffer_clear(buffer);
648 if(udpsize < sldns_buffer_limit(buffer))
649 sldns_buffer_set_limit(buffer, udpsize);
650 if(sldns_buffer_remaining(buffer) < LDNS_HEADER_SIZE)
653 sldns_buffer_write(buffer, &id, sizeof(uint16_t));
654 sldns_buffer_write_u16(buffer, flags);
655 sldns_buffer_write_u16(buffer, rep->qdcount);
656 /* set an, ns, ar counts to zero in case of small packets */
657 sldns_buffer_write(buffer, "\000\000\000\000\000\000", 6);
659 /* insert query section */
661 if((r=insert_query(qinfo, &tree, buffer, region)) !=
663 if(r == RETVAL_TRUNC) {
664 /* create truncated message */
665 sldns_buffer_write_u16_at(buffer, 4, 0);
666 LDNS_TC_SET(sldns_buffer_begin(buffer));
667 sldns_buffer_flip(buffer);
673 /* roundrobin offset. using query id for random number. With ntohs
674 * for different roundrobins for sequential id client senders. */
675 rr_offset = RRSET_ROUNDROBIN?ntohs(id):0;
677 /* "prepend" any local alias records in the answer section if this
678 * response is supposed to be authoritative. Currently it should
679 * be a single CNAME record (sanity-checked in worker_handle_request())
680 * but it can be extended if and when we support more variations of
682 if(qinfo->local_alias && (flags & BIT_AA)) {
683 struct reply_info arep;
684 time_t timezero = 0; /* to use the 'authoritative' TTL */
685 memset(&arep, 0, sizeof(arep));
686 arep.flags = rep->flags;
687 arep.an_numrrsets = 1;
688 arep.rrset_count = 1;
689 arep.rrsets = &qinfo->local_alias->rrset;
690 if((r=insert_section(&arep, 1, &ancount, buffer, 0,
691 timezero, region, &tree, LDNS_SECTION_ANSWER,
692 qinfo->qtype, dnssec, rr_offset)) != RETVAL_OK) {
693 if(r == RETVAL_TRUNC) {
694 /* create truncated message */
695 sldns_buffer_write_u16_at(buffer, 6, ancount);
696 LDNS_TC_SET(sldns_buffer_begin(buffer));
697 sldns_buffer_flip(buffer);
704 /* insert answer section */
705 if((r=insert_section(rep, rep->an_numrrsets, &ancount, buffer,
706 0, timenow, region, &tree, LDNS_SECTION_ANSWER, qinfo->qtype,
707 dnssec, rr_offset)) != RETVAL_OK) {
708 if(r == RETVAL_TRUNC) {
709 /* create truncated message */
710 sldns_buffer_write_u16_at(buffer, 6, ancount);
711 LDNS_TC_SET(sldns_buffer_begin(buffer));
712 sldns_buffer_flip(buffer);
717 sldns_buffer_write_u16_at(buffer, 6, ancount);
719 /* if response is positive answer, auth/add sections are not required */
720 if( ! (MINIMAL_RESPONSES && positive_answer(rep, qinfo->qtype)) ) {
721 /* insert auth section */
722 if((r=insert_section(rep, rep->ns_numrrsets, &nscount, buffer,
723 rep->an_numrrsets, timenow, region, &tree,
724 LDNS_SECTION_AUTHORITY, qinfo->qtype,
725 dnssec, rr_offset)) != RETVAL_OK) {
726 if(r == RETVAL_TRUNC) {
727 /* create truncated message */
728 sldns_buffer_write_u16_at(buffer, 8, nscount);
729 LDNS_TC_SET(sldns_buffer_begin(buffer));
730 sldns_buffer_flip(buffer);
735 sldns_buffer_write_u16_at(buffer, 8, nscount);
737 /* insert add section */
738 if((r=insert_section(rep, rep->ar_numrrsets, &arcount, buffer,
739 rep->an_numrrsets + rep->ns_numrrsets, timenow, region,
740 &tree, LDNS_SECTION_ADDITIONAL, qinfo->qtype,
741 dnssec, rr_offset)) != RETVAL_OK) {
742 if(r == RETVAL_TRUNC) {
743 /* no need to set TC bit, this is the additional */
744 sldns_buffer_write_u16_at(buffer, 10, arcount);
745 sldns_buffer_flip(buffer);
750 sldns_buffer_write_u16_at(buffer, 10, arcount);
752 sldns_buffer_flip(buffer);
757 calc_edns_field_size(struct edns_data* edns)
760 struct edns_option* opt;
761 if(!edns || !edns->edns_present)
763 for(opt = edns->opt_list; opt; opt = opt->next) {
764 rdatalen += 4 + opt->opt_len;
766 /* domain root '.' + type + class + ttl + rdatalen */
767 return 1 + 2 + 2 + 4 + 2 + rdatalen;
771 attach_edns_record(sldns_buffer* pkt, struct edns_data* edns)
775 struct edns_option* opt;
776 if(!edns || !edns->edns_present)
778 /* inc additional count */
779 sldns_buffer_write_u16_at(pkt, 10,
780 sldns_buffer_read_u16_at(pkt, 10) + 1);
781 len = sldns_buffer_limit(pkt);
782 sldns_buffer_clear(pkt);
783 sldns_buffer_set_position(pkt, len);
784 /* write EDNS record */
785 sldns_buffer_write_u8(pkt, 0); /* '.' label */
786 sldns_buffer_write_u16(pkt, LDNS_RR_TYPE_OPT); /* type */
787 sldns_buffer_write_u16(pkt, edns->udp_size); /* class */
788 sldns_buffer_write_u8(pkt, edns->ext_rcode); /* ttl */
789 sldns_buffer_write_u8(pkt, edns->edns_version);
790 sldns_buffer_write_u16(pkt, edns->bits);
791 rdatapos = sldns_buffer_position(pkt);
792 sldns_buffer_write_u16(pkt, 0); /* rdatalen */
794 for(opt=edns->opt_list; opt; opt=opt->next) {
795 sldns_buffer_write_u16(pkt, opt->opt_code);
796 sldns_buffer_write_u16(pkt, opt->opt_len);
797 if(opt->opt_len != 0)
798 sldns_buffer_write(pkt, opt->opt_data, opt->opt_len);
801 sldns_buffer_write_u16_at(pkt, rdatapos,
802 sldns_buffer_position(pkt)-rdatapos-2);
803 sldns_buffer_flip(pkt);
807 reply_info_answer_encode(struct query_info* qinf, struct reply_info* rep,
808 uint16_t id, uint16_t qflags, sldns_buffer* pkt, time_t timenow,
809 int cached, struct regional* region, uint16_t udpsize,
810 struct edns_data* edns, int dnssec, int secure)
815 if(!cached || rep->authoritative) {
816 /* original flags, copy RD and CD bits from query. */
817 flags = rep->flags | (qflags & (BIT_RD|BIT_CD));
819 /* remove AA bit, copy RD and CD bits from query. */
820 flags = (rep->flags & ~BIT_AA) | (qflags & (BIT_RD|BIT_CD));
822 if(secure && (dnssec || (qflags&BIT_AD)))
824 /* restore AA bit if we have a local alias and the response can be
825 * authoritative. Also clear AD bit if set as the local data is the
827 if(qinf->local_alias &&
828 (FLAGS_GET_RCODE(rep->flags) == LDNS_RCODE_NOERROR ||
829 FLAGS_GET_RCODE(rep->flags) == LDNS_RCODE_NXDOMAIN)) {
833 log_assert(flags & BIT_QR); /* QR bit must be on in our replies */
834 if(udpsize < LDNS_HEADER_SIZE)
836 if(udpsize < LDNS_HEADER_SIZE + calc_edns_field_size(edns)) {
837 /* packet too small to contain edns, omit it. */
840 /* reserve space for edns record */
841 udpsize -= calc_edns_field_size(edns);
844 if(!reply_info_encode(qinf, rep, id, flags, pkt, timenow, region,
846 log_err("reply encode: out of memory");
850 attach_edns_record(pkt, edns);
855 qinfo_query_encode(sldns_buffer* pkt, struct query_info* qinfo)
857 uint16_t flags = 0; /* QUERY, NOERROR */
858 const uint8_t* qname = qinfo->local_alias ?
859 qinfo->local_alias->rrset->rk.dname : qinfo->qname;
860 size_t qname_len = qinfo->local_alias ?
861 qinfo->local_alias->rrset->rk.dname_len : qinfo->qname_len;
862 sldns_buffer_clear(pkt);
863 log_assert(sldns_buffer_remaining(pkt) >= 12+255+4/*max query*/);
864 sldns_buffer_skip(pkt, 2); /* id done later */
865 sldns_buffer_write_u16(pkt, flags);
866 sldns_buffer_write_u16(pkt, 1); /* query count */
867 sldns_buffer_write(pkt, "\000\000\000\000\000\000", 6); /* counts */
868 sldns_buffer_write(pkt, qname, qname_len);
869 sldns_buffer_write_u16(pkt, qinfo->qtype);
870 sldns_buffer_write_u16(pkt, qinfo->qclass);
871 sldns_buffer_flip(pkt);
875 error_encode(sldns_buffer* buf, int r, struct query_info* qinfo,
876 uint16_t qid, uint16_t qflags, struct edns_data* edns)
880 sldns_buffer_clear(buf);
881 sldns_buffer_write(buf, &qid, sizeof(uint16_t));
882 flags = (uint16_t)(BIT_QR | BIT_RA | r); /* QR and retcode*/
883 flags |= (qflags & (BIT_RD|BIT_CD)); /* copy RD and CD bit */
884 sldns_buffer_write_u16(buf, flags);
887 sldns_buffer_write_u16(buf, flags);
889 sldns_buffer_write(buf, &flags, sizeof(uint16_t));
890 sldns_buffer_write(buf, &flags, sizeof(uint16_t));
891 sldns_buffer_write(buf, &flags, sizeof(uint16_t));
893 const uint8_t* qname = qinfo->local_alias ?
894 qinfo->local_alias->rrset->rk.dname : qinfo->qname;
895 size_t qname_len = qinfo->local_alias ?
896 qinfo->local_alias->rrset->rk.dname_len :
898 if(sldns_buffer_current(buf) == qname)
899 sldns_buffer_skip(buf, (ssize_t)qname_len);
900 else sldns_buffer_write(buf, qname, qname_len);
901 sldns_buffer_write_u16(buf, qinfo->qtype);
902 sldns_buffer_write_u16(buf, qinfo->qclass);
904 sldns_buffer_flip(buf);
906 struct edns_data es = *edns;
907 es.edns_version = EDNS_ADVERTISED_VERSION;
908 es.udp_size = EDNS_ADVERTISED_SIZE;
911 if(sldns_buffer_limit(buf) + calc_edns_field_size(&es) >
914 attach_edns_record(buf, &es);