contrib/unbound/util/data/msgencode.c

   1 /*
   2  * util/data/msgencode.c - Encode DNS messages, queries and replies.
   3  *
   4  * Copyright (c) 2007, NLnet Labs. All rights reserved.
   5  *
   6  * This software is open source.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  *
  12  * Redistributions of source code must retain the above copyright notice,
  13  * this list of conditions and the following disclaimer.
  14  *
  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.
  18  *
  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.
  22  *
  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.
  34  */
  35
  36 /**
  37  * \file
  38  *
  39  * This file contains a routines to encode DNS messages.
  40  */
  41
  42 #include "config.h"
  43 #include "util/data/msgencode.h"
  44 #include "util/data/msgreply.h"
  45 #include "util/data/msgparse.h"
  46 #include "util/data/dname.h"
  47 #include "util/log.h"
  48 #include "util/regional.h"
  49 #include "util/net_help.h"
  50 #include "sldns/sbuffer.h"
  51 #include "services/localzone.h"
  52
  53 #ifdef HAVE_TIME_H
  54 #include <time.h>
  55 #endif
  56 #include <sys/time.h>
  57
  58 /** return code that means the function ran out of memory. negative so it does
  59  * not conflict with DNS rcodes. */
  60 #define RETVAL_OUTMEM   -2
  61 /** return code that means the data did not fit (completely) in the packet */
  62 #define RETVAL_TRUNC    -4
  63 /** return code that means all is peachy keen. Equal to DNS rcode NOERROR */
  64 #define RETVAL_OK       0
  65
  66 /**
  67  * Data structure to help domain name compression in outgoing messages.
  68  * A tree of dnames and their offsets in the packet is kept.
  69  * It is kept sorted, not canonical, but by label at least, so that after
  70  * a lookup of a name you know its closest match, and the parent from that
  71  * closest match. These are possible compression targets.
  72  *
  73  * It is a binary tree, not a rbtree or balanced tree, as the effort
  74  * of keeping it balanced probably outweighs usefulness (given typical
  75  * DNS packet size).
  76  */
  77 struct compress_tree_node {
  78         /** left node in tree, all smaller to this */
  79         struct compress_tree_node* left;
  80         /** right node in tree, all larger than this */
  81         struct compress_tree_node* right;
  82
  83         /** the parent node - not for tree, but zone parent. One less label */
  84         struct compress_tree_node* parent;
  85         /** the domain name for this node. Pointer to uncompressed memory. */
  86         uint8_t* dname;
  87         /** number of labels in domain name, kept to help compare func. */
  88         int labs;
  89         /** offset in packet that points to this dname */
  90         size_t offset;
  91 };
  92
  93 /**
  94  * Find domain name in tree, returns exact and closest match.
  95  * @param tree: root of tree.
  96  * @param dname: pointer to uncompressed dname.
  97  * @param labs: number of labels in domain name.
  98  * @param match: closest or exact match.
  99  *      guaranteed to be smaller or equal to the sought dname.
 100  *      can be null if the tree is empty.
 101  * @param matchlabels: number of labels that match with closest match.
 102  *      can be zero is there is no match.
 103  * @param insertpt: insert location for dname, if not found.
 104  * @return: 0 if no exact match.
 105  */
 106 static int
 107 compress_tree_search(struct compress_tree_node** tree, uint8_t* dname,
 108         int labs, struct compress_tree_node** match, int* matchlabels,
 109         struct compress_tree_node*** insertpt)
 110 {
 111         int c, n, closen=0;
 112         struct compress_tree_node* p = *tree;
 113         struct compress_tree_node* close = 0;
 114         struct compress_tree_node** prev = tree;
 115         while(p) {
 116                 if((c = dname_lab_cmp(dname, labs, p->dname, p->labs, &n))
 117                         == 0) {
 118                         *matchlabels = n;
 119                         *match = p;
 120                         return 1;
 121                 }
 122                 if(c<0) {
 123                         prev = &p->left;
 124                         p = p->left;
 125                 } else  {
 126                         closen = n;
 127                         close = p; /* p->dname is smaller than dname */
 128                         prev = &p->right;
 129                         p = p->right;
 130                 }
 131         }
 132         *insertpt = prev;
 133         *matchlabels = closen;
 134         *match = close;
 135         return 0;
 136 }
 137
 138 /**
 139  * Lookup a domain name in compression tree.
 140  * @param tree: root of tree (not the node with '.').
 141  * @param dname: pointer to uncompressed dname.
 142  * @param labs: number of labels in domain name.
 143  * @param insertpt: insert location for dname, if not found.
 144  * @return: 0 if not found or compress treenode with best compression.
 145  */
 146 static struct compress_tree_node*
 147 compress_tree_lookup(struct compress_tree_node** tree, uint8_t* dname,
 148         int labs, struct compress_tree_node*** insertpt)
 149 {
 150         struct compress_tree_node* p;
 151         int m;
 152         if(labs <= 1)
 153                 return 0; /* do not compress root node */
 154         if(compress_tree_search(tree, dname, labs, &p, &m, insertpt)) {
 155                 /* exact match */
 156                 return p;
 157         }
 158         /* return some ancestor of p that compresses well. */
 159         if(m>1) {
 160                 /* www.example.com. (labs=4) matched foo.example.com.(labs=4)
 161                  * then matchcount = 3. need to go up. */
 162                 while(p && p->labs > m)
 163                         p = p->parent;
 164                 return p;
 165         }
 166         return 0;
 167 }
 168
 169 /**
 170  * Create node for domain name compression tree.
 171  * @param dname: pointer to uncompressed dname (stored in tree).
 172  * @param labs: number of labels in dname.
 173  * @param offset: offset into packet for dname.
 174  * @param region: how to allocate memory for new node.
 175  * @return new node or 0 on malloc failure.
 176  */
 177 static struct compress_tree_node*
 178 compress_tree_newnode(uint8_t* dname, int labs, size_t offset,
 179         struct regional* region)
 180 {
 181         struct compress_tree_node* n = (struct compress_tree_node*)
 182                 regional_alloc(region, sizeof(struct compress_tree_node));
 183         if(!n) return 0;
 184         n->left = 0;
 185         n->right = 0;
 186         n->parent = 0;
 187         n->dname = dname;
 188         n->labs = labs;
 189         n->offset = offset;
 190         return n;
 191 }
 192
 193 /**
 194  * Store domain name and ancestors into compression tree.
 195  * @param dname: pointer to uncompressed dname (stored in tree).
 196  * @param labs: number of labels in dname.
 197  * @param offset: offset into packet for dname.
 198  * @param region: how to allocate memory for new node.
 199  * @param closest: match from previous lookup, used to compress dname.
 200  *      may be NULL if no previous match.
 201  *      if the tree has an ancestor of dname already, this must be it.
 202  * @param insertpt: where to insert the dname in tree.
 203  * @return: 0 on memory error.
 204  */
 205 static int
 206 compress_tree_store(uint8_t* dname, int labs, size_t offset,
 207         struct regional* region, struct compress_tree_node* closest,
 208         struct compress_tree_node** insertpt)
 209 {
 210         uint8_t lablen;
 211         struct compress_tree_node* newnode;
 212         struct compress_tree_node* prevnode = NULL;
 213         int uplabs = labs-1; /* does not store root in tree */
 214         if(closest) uplabs = labs - closest->labs;
 215         log_assert(uplabs >= 0);
 216         /* algorithms builds up a vine of dname-labels to hang into tree */
 217         while(uplabs--) {
 218                 if(offset > PTR_MAX_OFFSET) {
 219                         /* insertion failed, drop vine */
 220                         return 1; /* compression pointer no longer useful */
 221                 }
 222                 if(!(newnode = compress_tree_newnode(dname, labs, offset,
 223                         region))) {
 224                         /* insertion failed, drop vine */
 225                         return 0;
 226                 }
 227
 228                 if(prevnode) {
 229                         /* chain nodes together, last one has one label more,
 230                          * so is larger than newnode, thus goes right. */
 231                         newnode->right = prevnode;
 232                         prevnode->parent = newnode;
 233                 }
 234
 235                 /* next label */
 236                 lablen = *dname++;
 237                 dname += lablen;
 238                 offset += lablen+1;
 239                 prevnode = newnode;
 240                 labs--;
 241         }
 242         /* if we have a vine, hang the vine into the tree */
 243         if(prevnode) {
 244                 *insertpt = prevnode;
 245                 prevnode->parent = closest;
 246         }
 247         return 1;
 248 }
 249
 250 /** compress a domain name */
 251 static int
 252 write_compressed_dname(sldns_buffer* pkt, uint8_t* dname, int labs,
 253         struct compress_tree_node* p)
 254 {
 255         /* compress it */
 256         int labcopy = labs - p->labs;
 257         uint8_t lablen;
 258         uint16_t ptr;
 259
 260         if(labs == 1) {
 261                 /* write root label */
 262                 if(sldns_buffer_remaining(pkt) < 1)
 263                         return 0;
 264                 sldns_buffer_write_u8(pkt, 0);
 265                 return 1;
 266         }
 267
 268         /* copy the first couple of labels */
 269         while(labcopy--) {
 270                 lablen = *dname++;
 271                 if(sldns_buffer_remaining(pkt) < (size_t)lablen+1)
 272                         return 0;
 273                 sldns_buffer_write_u8(pkt, lablen);
 274                 sldns_buffer_write(pkt, dname, lablen);
 275                 dname += lablen;
 276         }
 277         /* insert compression ptr */
 278         if(sldns_buffer_remaining(pkt) < 2)
 279                 return 0;
 280         ptr = PTR_CREATE(p->offset);
 281         sldns_buffer_write_u16(pkt, ptr);
 282         return 1;
 283 }
 284
 285 /** compress owner name of RR, return RETVAL_OUTMEM RETVAL_TRUNC */
 286 static int
 287 compress_owner(struct ub_packed_rrset_key* key, sldns_buffer* pkt,
 288         struct regional* region, struct compress_tree_node** tree,
 289         size_t owner_pos, uint16_t* owner_ptr, int owner_labs)
 290 {
 291         struct compress_tree_node* p;
 292         struct compress_tree_node** insertpt = NULL;
 293         if(!*owner_ptr) {
 294                 /* compress first time dname */
 295                 if((p = compress_tree_lookup(tree, key->rk.dname,
 296                         owner_labs, &insertpt))) {
 297                         if(p->labs == owner_labs)
 298                                 /* avoid ptr chains, since some software is
 299                                  * not capable of decoding ptr after a ptr. */
 300                                 *owner_ptr = htons(PTR_CREATE(p->offset));
 301                         if(!write_compressed_dname(pkt, key->rk.dname,
 302                                 owner_labs, p))
 303                                 return RETVAL_TRUNC;
 304                         /* check if typeclass+4 ttl + rdatalen is available */
 305                         if(sldns_buffer_remaining(pkt) < 4+4+2)
 306                                 return RETVAL_TRUNC;
 307                 } else {
 308                         /* no compress */
 309                         if(sldns_buffer_remaining(pkt) < key->rk.dname_len+4+4+2)
 310                                 return RETVAL_TRUNC;
 311                         sldns_buffer_write(pkt, key->rk.dname,
 312                                 key->rk.dname_len);
 313                         if(owner_pos <= PTR_MAX_OFFSET)
 314                                 *owner_ptr = htons(PTR_CREATE(owner_pos));
 315                 }
 316                 if(!compress_tree_store(key->rk.dname, owner_labs,
 317                         owner_pos, region, p, insertpt))
 318                         return RETVAL_OUTMEM;
 319         } else {
 320                 /* always compress 2nd-further RRs in RRset */
 321                 if(owner_labs == 1) {
 322                         if(sldns_buffer_remaining(pkt) < 1+4+4+2)
 323                                 return RETVAL_TRUNC;
 324                         sldns_buffer_write_u8(pkt, 0);
 325                 } else {
 326                         if(sldns_buffer_remaining(pkt) < 2+4+4+2)
 327                                 return RETVAL_TRUNC;
 328                         sldns_buffer_write(pkt, owner_ptr, 2);
 329                 }
 330         }
 331         return RETVAL_OK;
 332 }
 333
 334 /** compress any domain name to the packet, return RETVAL_* */
 335 static int
 336 compress_any_dname(uint8_t* dname, sldns_buffer* pkt, int labs,
 337         struct regional* region, struct compress_tree_node** tree)
 338 {
 339         struct compress_tree_node* p;
 340         struct compress_tree_node** insertpt = NULL;
 341         size_t pos = sldns_buffer_position(pkt);
 342         if((p = compress_tree_lookup(tree, dname, labs, &insertpt))) {
 343                 if(!write_compressed_dname(pkt, dname, labs, p))
 344                         return RETVAL_TRUNC;
 345         } else {
 346                 if(!dname_buffer_write(pkt, dname))
 347                         return RETVAL_TRUNC;
 348         }
 349         if(!compress_tree_store(dname, labs, pos, region, p, insertpt))
 350                 return RETVAL_OUTMEM;
 351         return RETVAL_OK;
 352 }
 353
 354 /** return true if type needs domain name compression in rdata */
 355 static const sldns_rr_descriptor*
 356 type_rdata_compressable(struct ub_packed_rrset_key* key)
 357 {
 358         uint16_t t = ntohs(key->rk.type);
 359         if(sldns_rr_descript(t) &&
 360                 sldns_rr_descript(t)->_compress == LDNS_RR_COMPRESS)
 361                 return sldns_rr_descript(t);
 362         return 0;
 363 }
 364
 365 /** compress domain names in rdata, return RETVAL_* */
 366 static int
 367 compress_rdata(sldns_buffer* pkt, uint8_t* rdata, size_t todolen,
 368         struct regional* region, struct compress_tree_node** tree,
 369         const sldns_rr_descriptor* desc)
 370 {
 371         int labs, r, rdf = 0;
 372         size_t dname_len, len, pos = sldns_buffer_position(pkt);
 373         uint8_t count = desc->_dname_count;
 374
 375         sldns_buffer_skip(pkt, 2); /* rdata len fill in later */
 376         /* space for rdatalen checked for already */
 377         rdata += 2;
 378         todolen -= 2;
 379         while(todolen > 0 && count) {
 380                 switch(desc->_wireformat[rdf]) {
 381                 case LDNS_RDF_TYPE_DNAME:
 382                         labs = dname_count_size_labels(rdata, &dname_len);
 383                         if((r=compress_any_dname(rdata, pkt, labs, region,
 384                                 tree)) != RETVAL_OK)
 385                                 return r;
 386                         rdata += dname_len;
 387                         todolen -= dname_len;
 388                         count--;
 389                         len = 0;
 390                         break;
 391                 case LDNS_RDF_TYPE_STR:
 392                         len = *rdata + 1;
 393                         break;
 394                 default:
 395                         len = get_rdf_size(desc->_wireformat[rdf]);
 396                 }
 397                 if(len) {
 398                         /* copy over */
 399                         if(sldns_buffer_remaining(pkt) < len)
 400                                 return RETVAL_TRUNC;
 401                         sldns_buffer_write(pkt, rdata, len);
 402                         todolen -= len;
 403                         rdata += len;
 404                 }
 405                 rdf++;
 406         }
 407         /* copy remainder */
 408         if(todolen > 0) {
 409                 if(sldns_buffer_remaining(pkt) < todolen)
 410                         return RETVAL_TRUNC;
 411                 sldns_buffer_write(pkt, rdata, todolen);
 412         }
 413
 414         /* set rdata len */
 415         sldns_buffer_write_u16_at(pkt, pos, sldns_buffer_position(pkt)-pos-2);
 416         return RETVAL_OK;
 417 }
 418
 419 /** Returns true if RR type should be included */
 420 static int
 421 rrset_belongs_in_reply(sldns_pkt_section s, uint16_t rrtype, uint16_t qtype,
 422         int dnssec)
 423 {
 424         if(dnssec)
 425                 return 1;
 426         /* skip non DNSSEC types, except if directly queried for */
 427         if(s == LDNS_SECTION_ANSWER) {
 428                 if(qtype == LDNS_RR_TYPE_ANY || qtype == rrtype)
 429                         return 1;
 430         }
 431         /* check DNSSEC-ness */
 432         switch(rrtype) {
 433                 case LDNS_RR_TYPE_SIG:
 434                 case LDNS_RR_TYPE_KEY:
 435                 case LDNS_RR_TYPE_NXT:
 436                 case LDNS_RR_TYPE_DS:
 437                 case LDNS_RR_TYPE_RRSIG:
 438                 case LDNS_RR_TYPE_NSEC:
 439                 case LDNS_RR_TYPE_DNSKEY:
 440                 case LDNS_RR_TYPE_NSEC3:
 441                 case LDNS_RR_TYPE_NSEC3PARAMS:
 442                         return 0;
 443         }
 444         return 1;
 445 }
 446
 447 /** store rrset in buffer in wireformat, return RETVAL_* */
 448 static int
 449 packed_rrset_encode(struct ub_packed_rrset_key* key, sldns_buffer* pkt,
 450         uint16_t* num_rrs, time_t timenow, struct regional* region,
 451         int do_data, int do_sig, struct compress_tree_node** tree,
 452         sldns_pkt_section s, uint16_t qtype, int dnssec, size_t rr_offset)
 453 {
 454         size_t i, j, owner_pos;
 455         int r, owner_labs;
 456         uint16_t owner_ptr = 0;
 457         time_t adjust = 0;
 458         struct packed_rrset_data* data = (struct packed_rrset_data*)
 459                 key->entry.data;
 460
 461         /* does this RR type belong in the answer? */
 462         if(!rrset_belongs_in_reply(s, ntohs(key->rk.type), qtype, dnssec))
 463                 return RETVAL_OK;
 464
 465         owner_labs = dname_count_labels(key->rk.dname);
 466         owner_pos = sldns_buffer_position(pkt);
 467
 468         /** Determine relative time adjustment for TTL values.
 469          * For an rrset with a fixed TTL, use the rrset's TTL as given. */
 470         if((key->rk.flags & PACKED_RRSET_FIXEDTTL) != 0)
 471                 adjust = 0;
 472         else
 473                 adjust = SERVE_ORIGINAL_TTL ? data->ttl_add : timenow;
 474
 475         if(do_data) {
 476                 const sldns_rr_descriptor* c = type_rdata_compressable(key);
 477                 for(i=0; i<data->count; i++) {
 478                         /* rrset roundrobin */
 479                         j = (i + rr_offset) % data->count;
 480                         if((r=compress_owner(key, pkt, region, tree,
 481                                 owner_pos, &owner_ptr, owner_labs))
 482                                 != RETVAL_OK)
 483                                 return r;
 484                         sldns_buffer_write(pkt, &key->rk.type, 2);
 485                         sldns_buffer_write(pkt, &key->rk.rrset_class, 2);
 486                         if(data->rr_ttl[j] < adjust)
 487                                 sldns_buffer_write_u32(pkt,
 488                                         SERVE_EXPIRED?SERVE_EXPIRED_REPLY_TTL:0);
 489                         else    sldns_buffer_write_u32(pkt, data->rr_ttl[j]-adjust);
 490                         if(c) {
 491                                 if((r=compress_rdata(pkt, data->rr_data[j],
 492                                         data->rr_len[j], region, tree, c))
 493                                         != RETVAL_OK)
 494                                         return r;
 495                         } else {
 496                                 if(sldns_buffer_remaining(pkt) < data->rr_len[j])
 497                                         return RETVAL_TRUNC;
 498                                 sldns_buffer_write(pkt, data->rr_data[j],
 499                                         data->rr_len[j]);
 500                         }
 501                 }
 502         }
 503         /* insert rrsigs */
 504         if(do_sig && dnssec) {
 505                 size_t total = data->count+data->rrsig_count;
 506                 for(i=data->count; i<total; i++) {
 507                         if(owner_ptr && owner_labs != 1) {
 508                                 if(sldns_buffer_remaining(pkt) <
 509                                         2+4+4+data->rr_len[i])
 510                                         return RETVAL_TRUNC;
 511                                 sldns_buffer_write(pkt, &owner_ptr, 2);
 512                         } else {
 513                                 if((r=compress_any_dname(key->rk.dname,
 514                                         pkt, owner_labs, region, tree))
 515                                         != RETVAL_OK)
 516                                         return r;
 517                                 if(sldns_buffer_remaining(pkt) <
 518                                         4+4+data->rr_len[i])
 519                                         return RETVAL_TRUNC;
 520                         }
 521                         sldns_buffer_write_u16(pkt, LDNS_RR_TYPE_RRSIG);
 522                         sldns_buffer_write(pkt, &key->rk.rrset_class, 2);
 523                         if(data->rr_ttl[i] < adjust)
 524                                 sldns_buffer_write_u32(pkt,
 525                                         SERVE_EXPIRED?SERVE_EXPIRED_REPLY_TTL:0);
 526                         else    sldns_buffer_write_u32(pkt, data->rr_ttl[i]-adjust);
 527                         /* rrsig rdata cannot be compressed, perform 100+ byte
 528                          * memcopy. */
 529                         sldns_buffer_write(pkt, data->rr_data[i],
 530                                 data->rr_len[i]);
 531                 }
 532         }
 533         /* change rrnum only after we are sure it fits */
 534         if(do_data)
 535                 *num_rrs += data->count;
 536         if(do_sig && dnssec)
 537                 *num_rrs += data->rrsig_count;
 538
 539         return RETVAL_OK;
 540 }
 541
 542 /** store msg section in wireformat buffer, return RETVAL_* */
 543 static int
 544 insert_section(struct reply_info* rep, size_t num_rrsets, uint16_t* num_rrs,
 545         sldns_buffer* pkt, size_t rrsets_before, time_t timenow,
 546         struct regional* region, struct compress_tree_node** tree,
 547         sldns_pkt_section s, uint16_t qtype, int dnssec, size_t rr_offset)
 548 {
 549         int r;
 550         size_t i, setstart;
 551         /* we now allow this function to be called multiple times for the
 552          * same section, incrementally updating num_rrs.  The caller is
 553          * responsible for initializing it (which is the case in the current
 554          * implementation). */
 555
 556         if(s != LDNS_SECTION_ADDITIONAL) {
 557                 if(s == LDNS_SECTION_ANSWER && qtype == LDNS_RR_TYPE_ANY)
 558                         dnssec = 1; /* include all types in ANY answer */
 559                 for(i=0; i<num_rrsets; i++) {
 560                         setstart = sldns_buffer_position(pkt);
 561                         if((r=packed_rrset_encode(rep->rrsets[rrsets_before+i],
 562                                 pkt, num_rrs, timenow, region, 1, 1, tree,
 563                                 s, qtype, dnssec, rr_offset))
 564                                 != RETVAL_OK) {
 565                                 /* Bad, but if due to size must set TC bit */
 566                                 /* trim off the rrset neatly. */
 567                                 sldns_buffer_set_position(pkt, setstart);
 568                                 return r;
 569                         }
 570                 }
 571         } else {
 572                 for(i=0; i<num_rrsets; i++) {
 573                         setstart = sldns_buffer_position(pkt);
 574                         if((r=packed_rrset_encode(rep->rrsets[rrsets_before+i],
 575                                 pkt, num_rrs, timenow, region, 1, 0, tree,
 576                                 s, qtype, dnssec, rr_offset))
 577                                 != RETVAL_OK) {
 578                                 sldns_buffer_set_position(pkt, setstart);
 579                                 return r;
 580                         }
 581                 }
 582                 if(dnssec)
 583                   for(i=0; i<num_rrsets; i++) {
 584                         setstart = sldns_buffer_position(pkt);
 585                         if((r=packed_rrset_encode(rep->rrsets[rrsets_before+i],
 586                                 pkt, num_rrs, timenow, region, 0, 1, tree,
 587                                 s, qtype, dnssec, rr_offset))
 588                                 != RETVAL_OK) {
 589                                 sldns_buffer_set_position(pkt, setstart);
 590                                 return r;
 591                         }
 592                   }
 593         }
 594         return RETVAL_OK;
 595 }
 596
 597 /** store query section in wireformat buffer, return RETVAL */
 598 static int
 599 insert_query(struct query_info* qinfo, struct compress_tree_node** tree,
 600         sldns_buffer* buffer, struct regional* region)
 601 {
 602         uint8_t* qname = qinfo->local_alias ?
 603                 qinfo->local_alias->rrset->rk.dname : qinfo->qname;
 604         size_t qname_len = qinfo->local_alias ?
 605                 qinfo->local_alias->rrset->rk.dname_len : qinfo->qname_len;
 606         if(sldns_buffer_remaining(buffer) <
 607                 qinfo->qname_len+sizeof(uint16_t)*2)
 608                 return RETVAL_TRUNC; /* buffer too small */
 609         /* the query is the first name inserted into the tree */
 610         if(!compress_tree_store(qname, dname_count_labels(qname),
 611                 sldns_buffer_position(buffer), region, NULL, tree))
 612                 return RETVAL_OUTMEM;
 613         if(sldns_buffer_current(buffer) == qname)
 614                 sldns_buffer_skip(buffer, (ssize_t)qname_len);
 615         else    sldns_buffer_write(buffer, qname, qname_len);
 616         sldns_buffer_write_u16(buffer, qinfo->qtype);
 617         sldns_buffer_write_u16(buffer, qinfo->qclass);
 618         return RETVAL_OK;
 619 }
 620
 621 static int
 622 positive_answer(struct reply_info* rep, uint16_t qtype) {
 623         size_t i;
 624         if (FLAGS_GET_RCODE(rep->flags) != LDNS_RCODE_NOERROR)
 625                 return 0;
 626
 627         for(i=0;i<rep->an_numrrsets; i++) {
 628                 if(ntohs(rep->rrsets[i]->rk.type) == qtype) {
 629                         /* for priming queries, type NS, include addresses */
 630                         if(qtype == LDNS_RR_TYPE_NS)
 631                                 return 0;
 632                         /* in case it is a wildcard with DNSSEC, there will
 633                          * be NSEC/NSEC3 records in the authority section
 634                          * that we cannot remove */
 635                         for(i=rep->an_numrrsets; i<rep->an_numrrsets+
 636                                 rep->ns_numrrsets; i++) {
 637                                 if(ntohs(rep->rrsets[i]->rk.type) ==
 638                                         LDNS_RR_TYPE_NSEC ||
 639                                    ntohs(rep->rrsets[i]->rk.type) ==
 640                                         LDNS_RR_TYPE_NSEC3)
 641                                         return 0;
 642                         }
 643                         return 1;
 644                 }
 645         }
 646         return 0;
 647 }
 648
 649 static int
 650 negative_answer(struct reply_info* rep) {
 651         size_t i;
 652         int ns_seen = 0;
 653         if(FLAGS_GET_RCODE(rep->flags) == LDNS_RCODE_NXDOMAIN)
 654                 return 1;
 655         if(FLAGS_GET_RCODE(rep->flags) == LDNS_RCODE_NOERROR &&
 656                 rep->an_numrrsets != 0)
 657                 return 0; /* positive */
 658         if(FLAGS_GET_RCODE(rep->flags) != LDNS_RCODE_NOERROR &&
 659                 FLAGS_GET_RCODE(rep->flags) != LDNS_RCODE_NXDOMAIN)
 660                 return 0;
 661         for(i=rep->an_numrrsets; i<rep->an_numrrsets+rep->ns_numrrsets; i++){
 662                 if(ntohs(rep->rrsets[i]->rk.type) == LDNS_RR_TYPE_SOA)
 663                         return 1;
 664                 if(ntohs(rep->rrsets[i]->rk.type) == LDNS_RR_TYPE_NS)
 665                         ns_seen = 1;
 666         }
 667         if(ns_seen) return 0; /* could be referral, NS, but no SOA */
 668         return 1;
 669 }
 670
 671 int
 672 reply_info_encode(struct query_info* qinfo, struct reply_info* rep,
 673         uint16_t id, uint16_t flags, sldns_buffer* buffer, time_t timenow,
 674         struct regional* region, uint16_t udpsize, int dnssec, int minimise)
 675 {
 676         uint16_t ancount=0, nscount=0, arcount=0;
 677         struct compress_tree_node* tree = 0;
 678         int r;
 679         size_t rr_offset;
 680
 681         sldns_buffer_clear(buffer);
 682         if(udpsize < sldns_buffer_limit(buffer))
 683                 sldns_buffer_set_limit(buffer, udpsize);
 684         if(sldns_buffer_remaining(buffer) < LDNS_HEADER_SIZE)
 685                 return 0;
 686
 687         sldns_buffer_write(buffer, &id, sizeof(uint16_t));
 688         sldns_buffer_write_u16(buffer, flags);
 689         sldns_buffer_write_u16(buffer, rep->qdcount);
 690         /* set an, ns, ar counts to zero in case of small packets */
 691         sldns_buffer_write(buffer, "\000\000\000\000\000\000", 6);
 692
 693         /* insert query section */
 694         if(rep->qdcount) {
 695                 if((r=insert_query(qinfo, &tree, buffer, region)) !=
 696                         RETVAL_OK) {
 697                         if(r == RETVAL_TRUNC) {
 698                                 /* create truncated message */
 699                                 sldns_buffer_write_u16_at(buffer, 4, 0);
 700                                 LDNS_TC_SET(sldns_buffer_begin(buffer));
 701                                 sldns_buffer_flip(buffer);
 702                                 return 1;
 703                         }
 704                         return 0;
 705                 }
 706         }
 707         /* roundrobin offset. using query id for random number.  With ntohs
 708          * for different roundrobins for sequential id client senders. */
 709         rr_offset = RRSET_ROUNDROBIN?ntohs(id)+(timenow?timenow:time(NULL)):0;
 710
 711         /* "prepend" any local alias records in the answer section if this
 712          * response is supposed to be authoritative.  Currently it should
 713          * be a single CNAME record (sanity-checked in worker_handle_request())
 714          * but it can be extended if and when we support more variations of
 715          * aliases. */
 716         if(qinfo->local_alias && (flags & BIT_AA)) {
 717                 struct reply_info arep;
 718                 time_t timezero = 0; /* to use the 'authoritative' TTL */
 719                 memset(&arep, 0, sizeof(arep));
 720                 arep.flags = rep->flags;
 721                 arep.an_numrrsets = 1;
 722                 arep.rrset_count = 1;
 723                 arep.rrsets = &qinfo->local_alias->rrset;
 724                 if((r=insert_section(&arep, 1, &ancount, buffer, 0,
 725                         timezero, region, &tree, LDNS_SECTION_ANSWER,
 726                         qinfo->qtype, dnssec, rr_offset)) != RETVAL_OK) {
 727                         if(r == RETVAL_TRUNC) {
 728                                 /* create truncated message */
 729                                 sldns_buffer_write_u16_at(buffer, 6, ancount);
 730                                 LDNS_TC_SET(sldns_buffer_begin(buffer));
 731                                 sldns_buffer_flip(buffer);
 732                                 return 1;
 733                         }
 734                         return 0;
 735                 }
 736         }
 737
 738         /* insert answer section */
 739         if((r=insert_section(rep, rep->an_numrrsets, &ancount, buffer,
 740                 0, timenow, region, &tree, LDNS_SECTION_ANSWER, qinfo->qtype,
 741                 dnssec, rr_offset)) != RETVAL_OK) {
 742                 if(r == RETVAL_TRUNC) {
 743                         /* create truncated message */
 744                         sldns_buffer_write_u16_at(buffer, 6, ancount);
 745                         LDNS_TC_SET(sldns_buffer_begin(buffer));
 746                         sldns_buffer_flip(buffer);
 747                         return 1;
 748                 }
 749                 return 0;
 750         }
 751         sldns_buffer_write_u16_at(buffer, 6, ancount);
 752
 753         /* if response is positive answer, auth/add sections are not required */
 754         if( ! (minimise && positive_answer(rep, qinfo->qtype)) ) {
 755                 /* insert auth section */
 756                 if((r=insert_section(rep, rep->ns_numrrsets, &nscount, buffer,
 757                         rep->an_numrrsets, timenow, region, &tree,
 758                         LDNS_SECTION_AUTHORITY, qinfo->qtype,
 759                         dnssec, rr_offset)) != RETVAL_OK) {
 760                         if(r == RETVAL_TRUNC) {
 761                                 /* create truncated message */
 762                                 sldns_buffer_write_u16_at(buffer, 8, nscount);
 763                                 LDNS_TC_SET(sldns_buffer_begin(buffer));
 764                                 sldns_buffer_flip(buffer);
 765                                 return 1;
 766                         }
 767                         return 0;
 768                 }
 769                 sldns_buffer_write_u16_at(buffer, 8, nscount);
 770
 771                 if(! (minimise && negative_answer(rep))) {
 772                         /* insert add section */
 773                         if((r=insert_section(rep, rep->ar_numrrsets, &arcount, buffer,
 774                                 rep->an_numrrsets + rep->ns_numrrsets, timenow, region,
 775                                 &tree, LDNS_SECTION_ADDITIONAL, qinfo->qtype,
 776                                 dnssec, rr_offset)) != RETVAL_OK) {
 777                                 if(r == RETVAL_TRUNC) {
 778                                         /* no need to set TC bit, this is the additional */
 779                                         sldns_buffer_write_u16_at(buffer, 10, arcount);
 780                                         sldns_buffer_flip(buffer);
 781                                         return 1;
 782                                 }
 783                                 return 0;
 784                         }
 785                         sldns_buffer_write_u16_at(buffer, 10, arcount);
 786                 }
 787         }
 788         sldns_buffer_flip(buffer);
 789         return 1;
 790 }
 791
 792 uint16_t
 793 calc_edns_field_size(struct edns_data* edns)
 794 {
 795         size_t rdatalen = 0;
 796         struct edns_option* opt;
 797         if(!edns || !edns->edns_present)
 798                 return 0;
 799         for(opt = edns->opt_list_inplace_cb_out; opt; opt = opt->next) {
 800                 rdatalen += 4 + opt->opt_len;
 801         }
 802         for(opt = edns->opt_list_out; opt; opt = opt->next) {
 803                 rdatalen += 4 + opt->opt_len;
 804         }
 805         /* domain root '.' + type + class + ttl + rdatalen */
 806         return 1 + 2 + 2 + 4 + 2 + rdatalen;
 807 }
 808
 809 uint16_t
 810 calc_edns_option_size(struct edns_data* edns, uint16_t code)
 811 {
 812         size_t rdatalen = 0;
 813         struct edns_option* opt;
 814         if(!edns || !edns->edns_present)
 815                 return 0;
 816         for(opt = edns->opt_list_inplace_cb_out; opt; opt = opt->next) {
 817                 if(opt->opt_code == code)
 818                         rdatalen += 4 + opt->opt_len;
 819         }
 820         for(opt = edns->opt_list_out; opt; opt = opt->next) {
 821                 if(opt->opt_code == code)
 822                         rdatalen += 4 + opt->opt_len;
 823         }
 824         return rdatalen;
 825 }
 826
 827 uint16_t
 828 calc_ede_option_size(struct edns_data* edns, uint16_t* txt_size)
 829 {
 830         size_t rdatalen = 0;
 831         struct edns_option* opt;
 832         *txt_size = 0;
 833         if(!edns || !edns->edns_present)
 834                 return 0;
 835         for(opt = edns->opt_list_inplace_cb_out; opt; opt = opt->next) {
 836                 if(opt->opt_code == LDNS_EDNS_EDE) {
 837                         rdatalen += 4 + opt->opt_len;
 838                         if(opt->opt_len > 2) *txt_size += opt->opt_len - 2;
 839                         if(opt->opt_len >= 2 && sldns_read_uint16(
 840                                 opt->opt_data) == LDNS_EDE_OTHER) {
 841                                 *txt_size += 4 + 2;
 842                         }
 843                 }
 844         }
 845         for(opt = edns->opt_list_out; opt; opt = opt->next) {
 846                 if(opt->opt_code == LDNS_EDNS_EDE) {
 847                         rdatalen += 4 + opt->opt_len;
 848                         if(opt->opt_len > 2) *txt_size += opt->opt_len - 2;
 849                         if(opt->opt_len >= 2 && sldns_read_uint16(
 850                                 opt->opt_data) == LDNS_EDE_OTHER) {
 851                                 *txt_size += 4 + 2;
 852                         }
 853                 }
 854         }
 855         return rdatalen;
 856 }
 857
 858 /* Trims the EDE OPTION-DATA to not include any EXTRA-TEXT data.
 859  * Also removes any LDNS_EDE_OTHER options from the list since they are useless
 860  * without the extra text. */
 861 static void
 862 ede_trim_text(struct edns_option** list)
 863 {
 864         struct edns_option* curr, *prev = NULL;
 865         if(!list || !(*list)) return;
 866         /* Unlink and repoint if LDNS_EDE_OTHER are first in list */
 867         while(list && *list && (*list)->opt_code == LDNS_EDNS_EDE
 868                 && (*list)->opt_len >= 2
 869                 && sldns_read_uint16((*list)->opt_data) == LDNS_EDE_OTHER ) {
 870                 *list = (*list)->next;
 871         }
 872         if(!list || !(*list)) return;
 873         curr = *list;
 874         while(curr) {
 875                 if(curr->opt_code == LDNS_EDNS_EDE) {
 876                         if(curr->opt_len >= 2 && sldns_read_uint16(
 877                                 curr->opt_data) == LDNS_EDE_OTHER) {
 878                                 /* LDNS_EDE_OTHER cannot be the first option in
 879                                  * this while, so prev is always initialized at
 880                                  * this point from the other branches;
 881                                  * cut this option off */
 882                                 prev->next = curr->next;
 883                                 curr = curr->next;
 884                         } else if(curr->opt_len > 2) {
 885                                 /* trim this option's EXTRA-TEXT */
 886                                 curr->opt_len = 2;
 887                                 prev = curr;
 888                                 curr = curr->next;
 889                         }
 890                 } else {
 891                         /* continue */
 892                         prev = curr;
 893                         curr = curr->next;
 894                 }
 895         }
 896 }
 897
 898 static void
 899 attach_edns_record_max_msg_sz(sldns_buffer* pkt, struct edns_data* edns,
 900         uint16_t max_msg_sz)
 901 {
 902         size_t len;
 903         size_t rdatapos;
 904         struct edns_option* opt;
 905         struct edns_option* padding_option = NULL;
 906         /* inc additional count */
 907         sldns_buffer_write_u16_at(pkt, 10,
 908                 sldns_buffer_read_u16_at(pkt, 10) + 1);
 909         len = sldns_buffer_limit(pkt);
 910         sldns_buffer_clear(pkt);
 911         sldns_buffer_set_position(pkt, len);
 912         /* write EDNS record */
 913         sldns_buffer_write_u8(pkt, 0); /* '.' label */
 914         sldns_buffer_write_u16(pkt, LDNS_RR_TYPE_OPT); /* type */
 915         sldns_buffer_write_u16(pkt, edns->udp_size); /* class */
 916         sldns_buffer_write_u8(pkt, edns->ext_rcode); /* ttl */
 917         sldns_buffer_write_u8(pkt, edns->edns_version);
 918         sldns_buffer_write_u16(pkt, edns->bits);
 919         rdatapos = sldns_buffer_position(pkt);
 920         sldns_buffer_write_u16(pkt, 0); /* rdatalen */
 921         /* write rdata */
 922         for(opt=edns->opt_list_inplace_cb_out; opt; opt=opt->next) {
 923                 if (opt->opt_code == LDNS_EDNS_PADDING) {
 924                         padding_option = opt;
 925                         continue;
 926                 }
 927                 sldns_buffer_write_u16(pkt, opt->opt_code);
 928                 sldns_buffer_write_u16(pkt, opt->opt_len);
 929                 if(opt->opt_len != 0)
 930                         sldns_buffer_write(pkt, opt->opt_data, opt->opt_len);
 931         }
 932         for(opt=edns->opt_list_out; opt; opt=opt->next) {
 933                 if (opt->opt_code == LDNS_EDNS_PADDING) {
 934                         padding_option = opt;
 935                         continue;
 936                 }
 937                 sldns_buffer_write_u16(pkt, opt->opt_code);
 938                 sldns_buffer_write_u16(pkt, opt->opt_len);
 939                 if(opt->opt_len != 0)
 940                         sldns_buffer_write(pkt, opt->opt_data, opt->opt_len);
 941         }
 942         if (padding_option && edns->padding_block_size ) {
 943                 size_t pad_pos = sldns_buffer_position(pkt);
 944                 size_t msg_sz = ((pad_pos + 3) / edns->padding_block_size + 1)
 945                                                * edns->padding_block_size;
 946                 size_t pad_sz;
 947
 948                 if (msg_sz > max_msg_sz)
 949                         msg_sz = max_msg_sz;
 950
 951                 /* By use of calc_edns_field_size, calling functions should
 952                  * have made sure that there is enough space for at least a
 953                  * zero sized padding option.
 954                  */
 955                 log_assert(pad_pos + 4 <= msg_sz);
 956
 957                 pad_sz = msg_sz - pad_pos - 4;
 958                 sldns_buffer_write_u16(pkt, LDNS_EDNS_PADDING);
 959                 sldns_buffer_write_u16(pkt, pad_sz);
 960                 if (pad_sz) {
 961                         memset(sldns_buffer_current(pkt), 0, pad_sz);
 962                         sldns_buffer_skip(pkt, pad_sz);
 963                 }
 964         }
 965         sldns_buffer_write_u16_at(pkt, rdatapos,
 966                         sldns_buffer_position(pkt)-rdatapos-2);
 967         sldns_buffer_flip(pkt);
 968 }
 969
 970 void
 971 attach_edns_record(sldns_buffer* pkt, struct edns_data* edns)
 972 {
 973         if(!edns || !edns->edns_present)
 974                 return;
 975         attach_edns_record_max_msg_sz(pkt, edns, edns->udp_size);
 976 }
 977
 978 int
 979 reply_info_answer_encode(struct query_info* qinf, struct reply_info* rep,
 980         uint16_t id, uint16_t qflags, sldns_buffer* pkt, time_t timenow,
 981         int cached, struct regional* region, uint16_t udpsize,
 982         struct edns_data* edns, int dnssec, int secure)
 983 {
 984         uint16_t flags;
 985         unsigned int attach_edns = 0;
 986         uint16_t edns_field_size, ede_size, ede_txt_size;
 987
 988         if(!cached || rep->authoritative) {
 989                 /* original flags, copy RD and CD bits from query. */
 990                 flags = rep->flags | (qflags & (BIT_RD|BIT_CD));
 991         } else {
 992                 /* remove AA bit, copy RD and CD bits from query. */
 993                 flags = (rep->flags & ~BIT_AA) | (qflags & (BIT_RD|BIT_CD));
 994         }
 995         if(secure && (dnssec || (qflags&BIT_AD)))
 996                 flags |= BIT_AD;
 997         /* restore AA bit if we have a local alias and the response can be
 998          * authoritative.  Also clear AD bit if set as the local data is the
 999          * primary answer. */
1000         if(qinf->local_alias &&
1001                 (FLAGS_GET_RCODE(rep->flags) == LDNS_RCODE_NOERROR ||
1002                 FLAGS_GET_RCODE(rep->flags) == LDNS_RCODE_NXDOMAIN)) {
1003                 flags |= BIT_AA;
1004                 flags &= ~BIT_AD;
1005         }
1006         log_assert(flags & BIT_QR); /* QR bit must be on in our replies */
1007         if(udpsize < LDNS_HEADER_SIZE)
1008                 return 0;
1009         /* currently edns does not change during calculations;
1010          * calculate sizes once here */
1011         edns_field_size = calc_edns_field_size(edns);
1012         ede_size = calc_ede_option_size(edns, &ede_txt_size);
1013         if(sldns_buffer_capacity(pkt) < udpsize)
1014                 udpsize = sldns_buffer_capacity(pkt);
1015         /* EDEs are optional, try to fit anything else before them */
1016         if(udpsize < LDNS_HEADER_SIZE + edns_field_size - ede_size) {
1017                 /* packet too small to contain edns, omit it. */
1018                 attach_edns = 0;
1019         } else {
1020                 /* reserve space for edns record */
1021                 attach_edns = (unsigned int)edns_field_size - ede_size;
1022         }
1023
1024         if(!reply_info_encode(qinf, rep, id, flags, pkt, timenow, region,
1025                 udpsize - attach_edns, dnssec, MINIMAL_RESPONSES)) {
1026                 log_err("reply encode: out of memory");
1027                 return 0;
1028         }
1029         if(attach_edns) {
1030                 if(udpsize >= sldns_buffer_limit(pkt) + edns_field_size)
1031                         attach_edns_record_max_msg_sz(pkt, edns, udpsize);
1032                 else if(udpsize >= sldns_buffer_limit(pkt) + edns_field_size - ede_txt_size) {
1033                         ede_trim_text(&edns->opt_list_inplace_cb_out);
1034                         ede_trim_text(&edns->opt_list_out);
1035                         attach_edns_record_max_msg_sz(pkt, edns, udpsize);
1036                 } else if(udpsize >= sldns_buffer_limit(pkt) + edns_field_size - ede_size) {
1037                         edns_opt_list_remove(&edns->opt_list_inplace_cb_out, LDNS_EDNS_EDE);
1038                         edns_opt_list_remove(&edns->opt_list_out, LDNS_EDNS_EDE);
1039                         attach_edns_record_max_msg_sz(pkt, edns, udpsize);
1040                 }
1041         }
1042         return 1;
1043 }
1044
1045 void
1046 qinfo_query_encode(sldns_buffer* pkt, struct query_info* qinfo)
1047 {
1048         uint16_t flags = 0; /* QUERY, NOERROR */
1049         const uint8_t* qname = qinfo->local_alias ?
1050                 qinfo->local_alias->rrset->rk.dname : qinfo->qname;
1051         size_t qname_len = qinfo->local_alias ?
1052                 qinfo->local_alias->rrset->rk.dname_len : qinfo->qname_len;
1053         sldns_buffer_clear(pkt);
1054         log_assert(sldns_buffer_remaining(pkt) >= 12+255+4/*max query*/);
1055         sldns_buffer_skip(pkt, 2); /* id done later */
1056         sldns_buffer_write_u16(pkt, flags);
1057         sldns_buffer_write_u16(pkt, 1); /* query count */
1058         sldns_buffer_write(pkt, "\000\000\000\000\000\000", 6); /* counts */
1059         sldns_buffer_write(pkt, qname, qname_len);
1060         sldns_buffer_write_u16(pkt, qinfo->qtype);
1061         sldns_buffer_write_u16(pkt, qinfo->qclass);
1062         sldns_buffer_flip(pkt);
1063 }
1064
1065 void
1066 extended_error_encode(sldns_buffer* buf, uint16_t rcode,
1067         struct query_info* qinfo, uint16_t qid, uint16_t qflags,
1068         uint16_t xflags, struct edns_data* edns)
1069 {
1070         uint16_t flags;
1071
1072         sldns_buffer_clear(buf);
1073         sldns_buffer_write(buf, &qid, sizeof(uint16_t));
1074         flags = (uint16_t)(BIT_QR | BIT_RA | (rcode & 0xF)); /* QR and retcode*/
1075         flags |= xflags;
1076         flags |= (qflags & (BIT_RD|BIT_CD)); /* copy RD and CD bit */
1077         sldns_buffer_write_u16(buf, flags);
1078         if(qinfo) flags = 1;
1079         else    flags = 0;
1080         sldns_buffer_write_u16(buf, flags);
1081         flags = 0;
1082         sldns_buffer_write(buf, &flags, sizeof(uint16_t));
1083         sldns_buffer_write(buf, &flags, sizeof(uint16_t));
1084         sldns_buffer_write(buf, &flags, sizeof(uint16_t));
1085         if(qinfo) {
1086                 const uint8_t* qname = qinfo->local_alias ?
1087                         qinfo->local_alias->rrset->rk.dname : qinfo->qname;
1088                 size_t qname_len = qinfo->local_alias ?
1089                         qinfo->local_alias->rrset->rk.dname_len :
1090                         qinfo->qname_len;
1091                 if(sldns_buffer_current(buf) == qname)
1092                         sldns_buffer_skip(buf, (ssize_t)qname_len);
1093                 else    sldns_buffer_write(buf, qname, qname_len);
1094                 sldns_buffer_write_u16(buf, qinfo->qtype);
1095                 sldns_buffer_write_u16(buf, qinfo->qclass);
1096         }
1097         sldns_buffer_flip(buf);
1098         if(edns) {
1099                 struct edns_data es = *edns;
1100                 es.edns_version = EDNS_ADVERTISED_VERSION;
1101                 es.udp_size = EDNS_ADVERTISED_SIZE;
1102                 es.ext_rcode = (uint8_t)(rcode >> 4);
1103                 es.bits &= EDNS_DO;
1104                 if(sldns_buffer_limit(buf) + calc_edns_field_size(&es) >
1105                         edns->udp_size) {
1106                         edns_opt_list_remove(&es.opt_list_inplace_cb_out, LDNS_EDNS_EDE);
1107                         edns_opt_list_remove(&es.opt_list_out, LDNS_EDNS_EDE);
1108                         if(sldns_buffer_limit(buf) + calc_edns_field_size(&es) >
1109                                 edns->udp_size) {
1110                                 return;
1111                         }
1112                 }
1113                 attach_edns_record(buf, &es);
1114         }
1115 }
1116
1117 void
1118 error_encode(sldns_buffer* buf, int r, struct query_info* qinfo,
1119         uint16_t qid, uint16_t qflags, struct edns_data* edns)
1120 {
1121         extended_error_encode(buf, (r & 0x000F), qinfo, qid, qflags,
1122                 (r & 0xFFF0), edns);
1123 }