1238106Sdes/* 2238106Sdes * util/data/msgparse.c - parse wireformat DNS messages. 3238106Sdes * 4238106Sdes * Copyright (c) 2007, NLnet Labs. All rights reserved. 5238106Sdes * 6238106Sdes * This software is open source. 7238106Sdes * 8238106Sdes * Redistribution and use in source and binary forms, with or without 9238106Sdes * modification, are permitted provided that the following conditions 10238106Sdes * are met: 11238106Sdes * 12238106Sdes * Redistributions of source code must retain the above copyright notice, 13238106Sdes * this list of conditions and the following disclaimer. 14238106Sdes * 15238106Sdes * Redistributions in binary form must reproduce the above copyright notice, 16238106Sdes * this list of conditions and the following disclaimer in the documentation 17238106Sdes * and/or other materials provided with the distribution. 18238106Sdes * 19238106Sdes * Neither the name of the NLNET LABS nor the names of its contributors may 20238106Sdes * be used to endorse or promote products derived from this software without 21238106Sdes * specific prior written permission. 22238106Sdes * 23238106Sdes * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 24238106Sdes * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 25238106Sdes * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 26238106Sdes * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE 27238106Sdes * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 28238106Sdes * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 29238106Sdes * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 30238106Sdes * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 31238106Sdes * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 32238106Sdes * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 33238106Sdes * POSSIBILITY OF SUCH DAMAGE. 34238106Sdes */ 35238106Sdes/** 36238106Sdes * \file 37238106Sdes * Routines for message parsing a packet buffer to a descriptive structure. 38238106Sdes */ 39238106Sdes#include "config.h" 40238106Sdes#include <ldns/ldns.h> 41238106Sdes#include "util/data/msgparse.h" 42238106Sdes#include "util/data/dname.h" 43238106Sdes#include "util/data/packed_rrset.h" 44238106Sdes#include "util/storage/lookup3.h" 45238106Sdes#include "util/regional.h" 46238106Sdes 47238106Sdes/** smart comparison of (compressed, valid) dnames from packet */ 48238106Sdesstatic int 49238106Sdessmart_compare(ldns_buffer* pkt, uint8_t* dnow, 50238106Sdes uint8_t* dprfirst, uint8_t* dprlast) 51238106Sdes{ 52238106Sdes if(LABEL_IS_PTR(*dnow)) { 53238106Sdes /* ptr points to a previous dname */ 54238106Sdes uint8_t* p = ldns_buffer_at(pkt, PTR_OFFSET(dnow[0], dnow[1])); 55238106Sdes if( p == dprfirst || p == dprlast ) 56238106Sdes return 0; 57238106Sdes /* prev dname is also a ptr, both ptrs are the same. */ 58238106Sdes if(LABEL_IS_PTR(*dprlast) && 59238106Sdes dprlast[0] == dnow[0] && dprlast[1] == dnow[1]) 60238106Sdes return 0; 61238106Sdes } 62238106Sdes return dname_pkt_compare(pkt, dnow, dprlast); 63238106Sdes} 64238106Sdes 65238106Sdes/** 66238106Sdes * Allocate new rrset in region, fill with data. 67238106Sdes */ 68238106Sdesstatic struct rrset_parse* 69238106Sdesnew_rrset(struct msg_parse* msg, uint8_t* dname, size_t dnamelen, 70238106Sdes uint16_t type, uint16_t dclass, hashvalue_t hash, 71238106Sdes uint32_t rrset_flags, ldns_pkt_section section, 72238106Sdes struct regional* region) 73238106Sdes{ 74238106Sdes struct rrset_parse* p = regional_alloc(region, sizeof(*p)); 75238106Sdes if(!p) return NULL; 76238106Sdes p->rrset_bucket_next = msg->hashtable[hash & (PARSE_TABLE_SIZE-1)]; 77238106Sdes msg->hashtable[hash & (PARSE_TABLE_SIZE-1)] = p; 78238106Sdes p->rrset_all_next = 0; 79238106Sdes if(msg->rrset_last) 80238106Sdes msg->rrset_last->rrset_all_next = p; 81238106Sdes else msg->rrset_first = p; 82238106Sdes msg->rrset_last = p; 83238106Sdes p->hash = hash; 84238106Sdes p->section = section; 85238106Sdes p->dname = dname; 86238106Sdes p->dname_len = dnamelen; 87238106Sdes p->type = type; 88238106Sdes p->rrset_class = dclass; 89238106Sdes p->flags = rrset_flags; 90238106Sdes p->rr_count = 0; 91238106Sdes p->size = 0; 92238106Sdes p->rr_first = 0; 93238106Sdes p->rr_last = 0; 94238106Sdes p->rrsig_count = 0; 95238106Sdes p->rrsig_first = 0; 96238106Sdes p->rrsig_last = 0; 97238106Sdes return p; 98238106Sdes} 99238106Sdes 100238106Sdes/** See if next rrset is nsec at zone apex */ 101238106Sdesstatic int 102238106Sdesnsec_at_apex(ldns_buffer* pkt) 103238106Sdes{ 104238106Sdes /* we are at ttl position in packet. */ 105238106Sdes size_t pos = ldns_buffer_position(pkt); 106238106Sdes uint16_t rdatalen; 107238106Sdes if(ldns_buffer_remaining(pkt) < 7) /* ttl+len+root */ 108238106Sdes return 0; /* eek! */ 109238106Sdes ldns_buffer_skip(pkt, 4); /* ttl */; 110238106Sdes rdatalen = ldns_buffer_read_u16(pkt); 111238106Sdes if(ldns_buffer_remaining(pkt) < rdatalen) { 112238106Sdes ldns_buffer_set_position(pkt, pos); 113238106Sdes return 0; /* parse error happens later */ 114238106Sdes } 115238106Sdes /* must validate the nsec next domain name format */ 116238106Sdes if(pkt_dname_len(pkt) == 0) { 117238106Sdes ldns_buffer_set_position(pkt, pos); 118238106Sdes return 0; /* parse error */ 119238106Sdes } 120238106Sdes 121238106Sdes /* see if SOA bit is set. */ 122238106Sdes if(ldns_buffer_position(pkt) < pos+4+rdatalen) { 123238106Sdes /* nsec type bitmap contains items */ 124238106Sdes uint8_t win, blen, bits; 125238106Sdes /* need: windownum, bitmap len, firstbyte */ 126238106Sdes if(ldns_buffer_position(pkt)+3 > pos+4+rdatalen) { 127238106Sdes ldns_buffer_set_position(pkt, pos); 128238106Sdes return 0; /* malformed nsec */ 129238106Sdes } 130238106Sdes win = ldns_buffer_read_u8(pkt); 131238106Sdes blen = ldns_buffer_read_u8(pkt); 132238106Sdes bits = ldns_buffer_read_u8(pkt); 133238106Sdes /* 0window always first window. bitlen >=1 or parse 134238106Sdes error really. bit 0x2 is SOA. */ 135238106Sdes if(win == 0 && blen >= 1 && (bits & 0x02)) { 136238106Sdes ldns_buffer_set_position(pkt, pos); 137238106Sdes return 1; 138238106Sdes } 139238106Sdes } 140238106Sdes 141238106Sdes ldns_buffer_set_position(pkt, pos); 142238106Sdes return 0; 143238106Sdes} 144238106Sdes 145238106Sdes/** Calculate rrset flags */ 146238106Sdesstatic uint32_t 147238106Sdespkt_rrset_flags(ldns_buffer* pkt, uint16_t type, ldns_pkt_section sec) 148238106Sdes{ 149238106Sdes uint32_t f = 0; 150238106Sdes if(type == LDNS_RR_TYPE_NSEC && nsec_at_apex(pkt)) { 151238106Sdes f |= PACKED_RRSET_NSEC_AT_APEX; 152238106Sdes } else if(type == LDNS_RR_TYPE_SOA && sec == LDNS_SECTION_AUTHORITY) { 153238106Sdes f |= PACKED_RRSET_SOA_NEG; 154238106Sdes } 155238106Sdes return f; 156238106Sdes} 157238106Sdes 158238106Sdeshashvalue_t 159238106Sdespkt_hash_rrset(ldns_buffer* pkt, uint8_t* dname, uint16_t type, 160238106Sdes uint16_t dclass, uint32_t rrset_flags) 161238106Sdes{ 162238106Sdes /* note this MUST be identical to rrset_key_hash in packed_rrset.c */ 163238106Sdes /* this routine handles compressed names */ 164238106Sdes hashvalue_t h = 0xab; 165238106Sdes h = dname_pkt_hash(pkt, dname, h); 166238106Sdes h = hashlittle(&type, sizeof(type), h); /* host order */ 167238106Sdes h = hashlittle(&dclass, sizeof(dclass), h); /* netw order */ 168238106Sdes h = hashlittle(&rrset_flags, sizeof(uint32_t), h); 169238106Sdes return h; 170238106Sdes} 171238106Sdes 172238106Sdes/** create partial dname hash for rrset hash */ 173238106Sdesstatic hashvalue_t 174238106Sdespkt_hash_rrset_first(ldns_buffer* pkt, uint8_t* dname) 175238106Sdes{ 176238106Sdes /* works together with pkt_hash_rrset_rest */ 177238106Sdes /* note this MUST be identical to rrset_key_hash in packed_rrset.c */ 178238106Sdes /* this routine handles compressed names */ 179238106Sdes hashvalue_t h = 0xab; 180238106Sdes h = dname_pkt_hash(pkt, dname, h); 181238106Sdes return h; 182238106Sdes} 183238106Sdes 184238106Sdes/** create a rrset hash from a partial dname hash */ 185238106Sdesstatic hashvalue_t 186238106Sdespkt_hash_rrset_rest(hashvalue_t dname_h, uint16_t type, uint16_t dclass, 187238106Sdes uint32_t rrset_flags) 188238106Sdes{ 189238106Sdes /* works together with pkt_hash_rrset_first */ 190238106Sdes /* note this MUST be identical to rrset_key_hash in packed_rrset.c */ 191238106Sdes hashvalue_t h; 192238106Sdes h = hashlittle(&type, sizeof(type), dname_h); /* host order */ 193238106Sdes h = hashlittle(&dclass, sizeof(dclass), h); /* netw order */ 194238106Sdes h = hashlittle(&rrset_flags, sizeof(uint32_t), h); 195238106Sdes return h; 196238106Sdes} 197238106Sdes 198238106Sdes/** compare rrset_parse with data */ 199238106Sdesstatic int 200238106Sdesrrset_parse_equals(struct rrset_parse* p, ldns_buffer* pkt, hashvalue_t h, 201238106Sdes uint32_t rrset_flags, uint8_t* dname, size_t dnamelen, 202238106Sdes uint16_t type, uint16_t dclass) 203238106Sdes{ 204238106Sdes if(p->hash == h && p->dname_len == dnamelen && p->type == type && 205238106Sdes p->rrset_class == dclass && p->flags == rrset_flags && 206238106Sdes dname_pkt_compare(pkt, dname, p->dname) == 0) 207238106Sdes return 1; 208238106Sdes return 0; 209238106Sdes} 210238106Sdes 211238106Sdes 212238106Sdesstruct rrset_parse* 213238106Sdesmsgparse_hashtable_lookup(struct msg_parse* msg, ldns_buffer* pkt, 214238106Sdes hashvalue_t h, uint32_t rrset_flags, uint8_t* dname, size_t dnamelen, 215238106Sdes uint16_t type, uint16_t dclass) 216238106Sdes{ 217238106Sdes struct rrset_parse* p = msg->hashtable[h & (PARSE_TABLE_SIZE-1)]; 218238106Sdes while(p) { 219238106Sdes if(rrset_parse_equals(p, pkt, h, rrset_flags, dname, dnamelen, 220238106Sdes type, dclass)) 221238106Sdes return p; 222238106Sdes p = p->rrset_bucket_next; 223238106Sdes } 224238106Sdes return NULL; 225238106Sdes} 226238106Sdes 227238106Sdes/** return type networkformat that rrsig in packet covers */ 228238106Sdesstatic int 229238106Sdespkt_rrsig_covered(ldns_buffer* pkt, uint8_t* here, uint16_t* type) 230238106Sdes{ 231238106Sdes size_t pos = ldns_buffer_position(pkt); 232238106Sdes ldns_buffer_set_position(pkt, (size_t)(here-ldns_buffer_begin(pkt))); 233238106Sdes /* ttl + len + size of small rrsig(rootlabel, no signature) */ 234238106Sdes if(ldns_buffer_remaining(pkt) < 4+2+19) 235238106Sdes return 0; 236238106Sdes ldns_buffer_skip(pkt, 4); /* ttl */ 237238106Sdes if(ldns_buffer_read_u16(pkt) < 19) /* too short */ { 238238106Sdes ldns_buffer_set_position(pkt, pos); 239238106Sdes return 0; 240238106Sdes } 241238106Sdes *type = ldns_buffer_read_u16(pkt); 242238106Sdes ldns_buffer_set_position(pkt, pos); 243238106Sdes return 1; 244238106Sdes} 245238106Sdes 246238106Sdes/** true if covered type equals prevtype */ 247238106Sdesstatic int 248238106Sdespkt_rrsig_covered_equals(ldns_buffer* pkt, uint8_t* here, uint16_t type) 249238106Sdes{ 250238106Sdes uint16_t t; 251238106Sdes if(pkt_rrsig_covered(pkt, here, &t) && t == type) 252238106Sdes return 1; 253238106Sdes return 0; 254238106Sdes} 255238106Sdes 256238106Sdesvoid 257238106Sdesmsgparse_bucket_remove(struct msg_parse* msg, struct rrset_parse* rrset) 258238106Sdes{ 259238106Sdes struct rrset_parse** p; 260238106Sdes p = &msg->hashtable[ rrset->hash & (PARSE_TABLE_SIZE-1) ]; 261238106Sdes while(*p) { 262238106Sdes if(*p == rrset) { 263238106Sdes *p = rrset->rrset_bucket_next; 264238106Sdes return; 265238106Sdes } 266238106Sdes p = &( (*p)->rrset_bucket_next ); 267238106Sdes } 268238106Sdes} 269238106Sdes 270238106Sdes/** change section of rrset from previous to current section */ 271238106Sdesstatic void 272238106Sdeschange_section(struct msg_parse* msg, struct rrset_parse* rrset, 273238106Sdes ldns_pkt_section section) 274238106Sdes{ 275238106Sdes struct rrset_parse *p, *prev; 276238106Sdes /* remove from list */ 277238106Sdes if(section == rrset->section) 278238106Sdes return; 279238106Sdes p = msg->rrset_first; 280238106Sdes prev = 0; 281238106Sdes while(p) { 282238106Sdes if(p == rrset) { 283238106Sdes if(prev) prev->rrset_all_next = p->rrset_all_next; 284238106Sdes else msg->rrset_first = p->rrset_all_next; 285238106Sdes if(msg->rrset_last == rrset) 286238106Sdes msg->rrset_last = prev; 287238106Sdes break; 288238106Sdes } 289238106Sdes prev = p; 290238106Sdes p = p->rrset_all_next; 291238106Sdes } 292238106Sdes /* remove from count */ 293238106Sdes switch(rrset->section) { 294238106Sdes case LDNS_SECTION_ANSWER: msg->an_rrsets--; break; 295238106Sdes case LDNS_SECTION_AUTHORITY: msg->ns_rrsets--; break; 296238106Sdes case LDNS_SECTION_ADDITIONAL: msg->ar_rrsets--; break; 297238106Sdes default: log_assert(0); 298238106Sdes } 299238106Sdes /* insert at end of list */ 300238106Sdes rrset->rrset_all_next = 0; 301238106Sdes if(msg->rrset_last) 302238106Sdes msg->rrset_last->rrset_all_next = rrset; 303238106Sdes else msg->rrset_first = rrset; 304238106Sdes msg->rrset_last = rrset; 305238106Sdes /* up count of new section */ 306238106Sdes switch(section) { 307238106Sdes case LDNS_SECTION_AUTHORITY: msg->ns_rrsets++; break; 308238106Sdes case LDNS_SECTION_ADDITIONAL: msg->ar_rrsets++; break; 309238106Sdes default: log_assert(0); 310238106Sdes } 311238106Sdes rrset->section = section; 312238106Sdes} 313238106Sdes 314238106Sdes/** see if rrset of type RRSIG contains sig over given type */ 315238106Sdesstatic int 316238106Sdesrrset_has_sigover(ldns_buffer* pkt, struct rrset_parse* rrset, uint16_t type, 317238106Sdes int* hasother) 318238106Sdes{ 319238106Sdes int res = 0; 320238106Sdes struct rr_parse* rr = rrset->rr_first; 321238106Sdes log_assert( rrset->type == LDNS_RR_TYPE_RRSIG ); 322238106Sdes while(rr) { 323238106Sdes if(pkt_rrsig_covered_equals(pkt, rr->ttl_data, type)) 324238106Sdes res = 1; 325238106Sdes else *hasother = 1; 326238106Sdes rr = rr->next; 327238106Sdes } 328238106Sdes return res; 329238106Sdes} 330238106Sdes 331238106Sdes/** move rrsigs from sigset to dataset */ 332238106Sdesstatic int 333238106Sdesmoveover_rrsigs(ldns_buffer* pkt, struct regional* region, 334238106Sdes struct rrset_parse* sigset, struct rrset_parse* dataset, int duplicate) 335238106Sdes{ 336238106Sdes struct rr_parse* sig = sigset->rr_first; 337238106Sdes struct rr_parse* prev = NULL; 338238106Sdes struct rr_parse* insert; 339238106Sdes struct rr_parse* nextsig; 340238106Sdes while(sig) { 341238106Sdes nextsig = sig->next; 342238106Sdes if(pkt_rrsig_covered_equals(pkt, sig->ttl_data, 343238106Sdes dataset->type)) { 344238106Sdes if(duplicate) { 345238106Sdes /* new */ 346238106Sdes insert = (struct rr_parse*)regional_alloc( 347238106Sdes region, sizeof(struct rr_parse)); 348238106Sdes if(!insert) return 0; 349238106Sdes insert->outside_packet = 0; 350238106Sdes insert->ttl_data = sig->ttl_data; 351238106Sdes insert->size = sig->size; 352238106Sdes /* prev not used */ 353238106Sdes } else { 354238106Sdes /* remove from sigset */ 355238106Sdes if(prev) prev->next = sig->next; 356238106Sdes else sigset->rr_first = sig->next; 357238106Sdes if(sigset->rr_last == sig) 358238106Sdes sigset->rr_last = prev; 359238106Sdes sigset->rr_count--; 360238106Sdes sigset->size -= sig->size; 361238106Sdes insert = sig; 362238106Sdes /* prev not changed */ 363238106Sdes } 364238106Sdes /* add to dataset */ 365238106Sdes dataset->rrsig_count++; 366238106Sdes insert->next = 0; 367238106Sdes if(dataset->rrsig_last) 368238106Sdes dataset->rrsig_last->next = insert; 369238106Sdes else dataset->rrsig_first = insert; 370238106Sdes dataset->rrsig_last = insert; 371238106Sdes dataset->size += insert->size; 372238106Sdes } else { 373238106Sdes prev = sig; 374238106Sdes } 375238106Sdes sig = nextsig; 376238106Sdes } 377238106Sdes return 1; 378238106Sdes} 379238106Sdes 380238106Sdes/** change an rrsig rrset for use as data rrset */ 381238106Sdesstatic struct rrset_parse* 382238106Sdeschange_rrsig_rrset(struct rrset_parse* sigset, struct msg_parse* msg, 383238106Sdes ldns_buffer* pkt, uint16_t datatype, uint32_t rrset_flags, 384238106Sdes int hasother, ldns_pkt_section section, struct regional* region) 385238106Sdes{ 386238106Sdes struct rrset_parse* dataset = sigset; 387238106Sdes hashvalue_t hash = pkt_hash_rrset(pkt, sigset->dname, datatype, 388238106Sdes sigset->rrset_class, rrset_flags); 389238106Sdes log_assert( sigset->type == LDNS_RR_TYPE_RRSIG ); 390238106Sdes log_assert( datatype != LDNS_RR_TYPE_RRSIG ); 391238106Sdes if(hasother) { 392238106Sdes /* need to make new rrset to hold data type */ 393238106Sdes dataset = new_rrset(msg, sigset->dname, sigset->dname_len, 394238106Sdes datatype, sigset->rrset_class, hash, rrset_flags, 395238106Sdes section, region); 396238106Sdes if(!dataset) 397238106Sdes return NULL; 398238106Sdes switch(section) { 399238106Sdes case LDNS_SECTION_ANSWER: msg->an_rrsets++; break; 400238106Sdes case LDNS_SECTION_AUTHORITY: msg->ns_rrsets++; break; 401238106Sdes case LDNS_SECTION_ADDITIONAL: msg->ar_rrsets++; break; 402238106Sdes default: log_assert(0); 403238106Sdes } 404238106Sdes if(!moveover_rrsigs(pkt, region, sigset, dataset, 405238106Sdes msg->qtype == LDNS_RR_TYPE_RRSIG || 406238106Sdes (msg->qtype == LDNS_RR_TYPE_ANY && 407238106Sdes section != LDNS_SECTION_ANSWER) )) 408238106Sdes return NULL; 409238106Sdes return dataset; 410238106Sdes } 411238106Sdes /* changeover the type of the rrset to data set */ 412238106Sdes msgparse_bucket_remove(msg, dataset); 413238106Sdes /* insert into new hash bucket */ 414238106Sdes dataset->rrset_bucket_next = msg->hashtable[hash&(PARSE_TABLE_SIZE-1)]; 415238106Sdes msg->hashtable[hash&(PARSE_TABLE_SIZE-1)] = dataset; 416238106Sdes dataset->hash = hash; 417238106Sdes /* use section of data item for result */ 418238106Sdes change_section(msg, dataset, section); 419238106Sdes dataset->type = datatype; 420238106Sdes dataset->flags = rrset_flags; 421238106Sdes dataset->rrsig_count += dataset->rr_count; 422238106Sdes dataset->rr_count = 0; 423238106Sdes /* move sigs to end of siglist */ 424238106Sdes if(dataset->rrsig_last) 425238106Sdes dataset->rrsig_last->next = dataset->rr_first; 426238106Sdes else dataset->rrsig_first = dataset->rr_first; 427238106Sdes dataset->rrsig_last = dataset->rr_last; 428238106Sdes dataset->rr_first = 0; 429238106Sdes dataset->rr_last = 0; 430238106Sdes return dataset; 431238106Sdes} 432238106Sdes 433238106Sdes/** Find rrset. If equal to previous it is fast. hash if not so. 434238106Sdes * @param msg: the message with hash table. 435238106Sdes * @param pkt: the packet in wireformat (needed for compression ptrs). 436238106Sdes * @param dname: pointer to start of dname (compressed) in packet. 437238106Sdes * @param dnamelen: uncompressed wirefmt length of dname. 438238106Sdes * @param type: type of current rr. 439238106Sdes * @param dclass: class of current rr. 440238106Sdes * @param hash: hash value is returned if the rrset could not be found. 441238106Sdes * @param rrset_flags: is returned if the rrset could not be found. 442238106Sdes * @param prev_dname_first: dname of last seen RR. First seen dname. 443238106Sdes * @param prev_dname_last: dname of last seen RR. Last seen dname. 444238106Sdes * @param prev_dnamelen: dname len of last seen RR. 445238106Sdes * @param prev_type: type of last seen RR. 446238106Sdes * @param prev_dclass: class of last seen RR. 447238106Sdes * @param rrset_prev: last seen RRset. 448238106Sdes * @param section: the current section in the packet. 449238106Sdes * @param region: used to allocate temporary parsing data. 450238106Sdes * @return 0 on out of memory. 451238106Sdes */ 452238106Sdesstatic int 453238106Sdesfind_rrset(struct msg_parse* msg, ldns_buffer* pkt, uint8_t* dname, 454238106Sdes size_t dnamelen, uint16_t type, uint16_t dclass, hashvalue_t* hash, 455238106Sdes uint32_t* rrset_flags, 456238106Sdes uint8_t** prev_dname_first, uint8_t** prev_dname_last, 457238106Sdes size_t* prev_dnamelen, uint16_t* prev_type, 458238106Sdes uint16_t* prev_dclass, struct rrset_parse** rrset_prev, 459238106Sdes ldns_pkt_section section, struct regional* region) 460238106Sdes{ 461238106Sdes hashvalue_t dname_h = pkt_hash_rrset_first(pkt, dname); 462238106Sdes uint16_t covtype; 463238106Sdes if(*rrset_prev) { 464238106Sdes /* check if equal to previous item */ 465238106Sdes if(type == *prev_type && dclass == *prev_dclass && 466238106Sdes dnamelen == *prev_dnamelen && 467238106Sdes smart_compare(pkt, dname, *prev_dname_first, 468238106Sdes *prev_dname_last) == 0 && 469238106Sdes type != LDNS_RR_TYPE_RRSIG) { 470238106Sdes /* same as previous */ 471238106Sdes *prev_dname_last = dname; 472238106Sdes return 1; 473238106Sdes } 474238106Sdes /* check if rrsig over previous item */ 475238106Sdes if(type == LDNS_RR_TYPE_RRSIG && dclass == *prev_dclass && 476238106Sdes pkt_rrsig_covered_equals(pkt, ldns_buffer_current(pkt), 477238106Sdes *prev_type) && 478238106Sdes smart_compare(pkt, dname, *prev_dname_first, 479238106Sdes *prev_dname_last) == 0) { 480238106Sdes /* covers previous */ 481238106Sdes *prev_dname_last = dname; 482238106Sdes return 1; 483238106Sdes } 484238106Sdes } 485238106Sdes /* find by hashing and lookup in hashtable */ 486238106Sdes *rrset_flags = pkt_rrset_flags(pkt, type, section); 487238106Sdes 488238106Sdes /* if rrsig - try to lookup matching data set first */ 489238106Sdes if(type == LDNS_RR_TYPE_RRSIG && pkt_rrsig_covered(pkt, 490238106Sdes ldns_buffer_current(pkt), &covtype)) { 491238106Sdes *hash = pkt_hash_rrset_rest(dname_h, covtype, dclass, 492238106Sdes *rrset_flags); 493238106Sdes *rrset_prev = msgparse_hashtable_lookup(msg, pkt, *hash, 494238106Sdes *rrset_flags, dname, dnamelen, covtype, dclass); 495238106Sdes if(!*rrset_prev && covtype == LDNS_RR_TYPE_NSEC) { 496238106Sdes /* if NSEC try with NSEC apex bit twiddled */ 497238106Sdes *rrset_flags ^= PACKED_RRSET_NSEC_AT_APEX; 498238106Sdes *hash = pkt_hash_rrset_rest(dname_h, covtype, dclass, 499238106Sdes *rrset_flags); 500238106Sdes *rrset_prev = msgparse_hashtable_lookup(msg, pkt, 501238106Sdes *hash, *rrset_flags, dname, dnamelen, covtype, 502238106Sdes dclass); 503238106Sdes if(!*rrset_prev) /* untwiddle if not found */ 504238106Sdes *rrset_flags ^= PACKED_RRSET_NSEC_AT_APEX; 505238106Sdes } 506238106Sdes if(!*rrset_prev && covtype == LDNS_RR_TYPE_SOA) { 507238106Sdes /* if SOA try with SOA neg flag twiddled */ 508238106Sdes *rrset_flags ^= PACKED_RRSET_SOA_NEG; 509238106Sdes *hash = pkt_hash_rrset_rest(dname_h, covtype, dclass, 510238106Sdes *rrset_flags); 511238106Sdes *rrset_prev = msgparse_hashtable_lookup(msg, pkt, 512238106Sdes *hash, *rrset_flags, dname, dnamelen, covtype, 513238106Sdes dclass); 514238106Sdes if(!*rrset_prev) /* untwiddle if not found */ 515238106Sdes *rrset_flags ^= PACKED_RRSET_SOA_NEG; 516238106Sdes } 517238106Sdes if(*rrset_prev) { 518238106Sdes *prev_dname_first = (*rrset_prev)->dname; 519238106Sdes *prev_dname_last = dname; 520238106Sdes *prev_dnamelen = dnamelen; 521238106Sdes *prev_type = covtype; 522238106Sdes *prev_dclass = dclass; 523238106Sdes return 1; 524238106Sdes } 525238106Sdes } 526238106Sdes if(type != LDNS_RR_TYPE_RRSIG) { 527238106Sdes int hasother = 0; 528238106Sdes /* find matching rrsig */ 529238106Sdes *hash = pkt_hash_rrset_rest(dname_h, LDNS_RR_TYPE_RRSIG, 530238106Sdes dclass, 0); 531238106Sdes *rrset_prev = msgparse_hashtable_lookup(msg, pkt, *hash, 532238106Sdes 0, dname, dnamelen, LDNS_RR_TYPE_RRSIG, 533238106Sdes dclass); 534238106Sdes if(*rrset_prev && rrset_has_sigover(pkt, *rrset_prev, type, 535238106Sdes &hasother)) { 536238106Sdes /* yes! */ 537238106Sdes *prev_dname_first = (*rrset_prev)->dname; 538238106Sdes *prev_dname_last = dname; 539238106Sdes *prev_dnamelen = dnamelen; 540238106Sdes *prev_type = type; 541238106Sdes *prev_dclass = dclass; 542238106Sdes *rrset_prev = change_rrsig_rrset(*rrset_prev, msg, 543238106Sdes pkt, type, *rrset_flags, hasother, section, 544238106Sdes region); 545238106Sdes if(!*rrset_prev) return 0; 546238106Sdes return 1; 547238106Sdes } 548238106Sdes } 549238106Sdes 550238106Sdes *hash = pkt_hash_rrset_rest(dname_h, type, dclass, *rrset_flags); 551238106Sdes *rrset_prev = msgparse_hashtable_lookup(msg, pkt, *hash, *rrset_flags, 552238106Sdes dname, dnamelen, type, dclass); 553238106Sdes if(*rrset_prev) 554238106Sdes *prev_dname_first = (*rrset_prev)->dname; 555238106Sdes else *prev_dname_first = dname; 556238106Sdes *prev_dname_last = dname; 557238106Sdes *prev_dnamelen = dnamelen; 558238106Sdes *prev_type = type; 559238106Sdes *prev_dclass = dclass; 560238106Sdes return 1; 561238106Sdes} 562238106Sdes 563238106Sdes/** 564238106Sdes * Parse query section. 565238106Sdes * @param pkt: packet, position at call must be at start of query section. 566238106Sdes * at end position is after query section. 567238106Sdes * @param msg: store results here. 568238106Sdes * @return: 0 if OK, or rcode on error. 569238106Sdes */ 570238106Sdesstatic int 571238106Sdesparse_query_section(ldns_buffer* pkt, struct msg_parse* msg) 572238106Sdes{ 573238106Sdes if(msg->qdcount == 0) 574238106Sdes return 0; 575238106Sdes if(msg->qdcount > 1) 576238106Sdes return LDNS_RCODE_FORMERR; 577238106Sdes log_assert(msg->qdcount == 1); 578238106Sdes if(ldns_buffer_remaining(pkt) <= 0) 579238106Sdes return LDNS_RCODE_FORMERR; 580238106Sdes msg->qname = ldns_buffer_current(pkt); 581238106Sdes if((msg->qname_len = pkt_dname_len(pkt)) == 0) 582238106Sdes return LDNS_RCODE_FORMERR; 583238106Sdes if(ldns_buffer_remaining(pkt) < sizeof(uint16_t)*2) 584238106Sdes return LDNS_RCODE_FORMERR; 585238106Sdes msg->qtype = ldns_buffer_read_u16(pkt); 586238106Sdes msg->qclass = ldns_buffer_read_u16(pkt); 587238106Sdes return 0; 588238106Sdes} 589238106Sdes 590238106Sdessize_t 591238106Sdesget_rdf_size(ldns_rdf_type rdf) 592238106Sdes{ 593238106Sdes switch(rdf) { 594238106Sdes case LDNS_RDF_TYPE_CLASS: 595238106Sdes case LDNS_RDF_TYPE_ALG: 596238106Sdes case LDNS_RDF_TYPE_INT8: 597238106Sdes return 1; 598238106Sdes break; 599238106Sdes case LDNS_RDF_TYPE_INT16: 600238106Sdes case LDNS_RDF_TYPE_TYPE: 601238106Sdes case LDNS_RDF_TYPE_CERT_ALG: 602238106Sdes return 2; 603238106Sdes break; 604238106Sdes case LDNS_RDF_TYPE_INT32: 605238106Sdes case LDNS_RDF_TYPE_TIME: 606238106Sdes case LDNS_RDF_TYPE_A: 607238106Sdes case LDNS_RDF_TYPE_PERIOD: 608238106Sdes return 4; 609238106Sdes break; 610238106Sdes case LDNS_RDF_TYPE_TSIGTIME: 611238106Sdes return 6; 612238106Sdes break; 613238106Sdes case LDNS_RDF_TYPE_AAAA: 614238106Sdes return 16; 615238106Sdes break; 616238106Sdes default: 617238106Sdes log_assert(false); /* add type above */ 618238106Sdes /* only types that appear before a domain * 619238106Sdes * name are needed. rest is simply copied. */ 620238106Sdes } 621238106Sdes return 0; 622238106Sdes} 623238106Sdes 624238106Sdes/** calculate the size of one rr */ 625238106Sdesstatic int 626238106Sdescalc_size(ldns_buffer* pkt, uint16_t type, struct rr_parse* rr) 627238106Sdes{ 628238106Sdes const ldns_rr_descriptor* desc; 629238106Sdes uint16_t pkt_len; /* length of rr inside the packet */ 630238106Sdes rr->size = sizeof(uint16_t); /* the rdatalen */ 631238106Sdes ldns_buffer_skip(pkt, 4); /* skip ttl */ 632238106Sdes pkt_len = ldns_buffer_read_u16(pkt); 633238106Sdes if(ldns_buffer_remaining(pkt) < pkt_len) 634238106Sdes return 0; 635238106Sdes desc = ldns_rr_descript(type); 636238106Sdes if(pkt_len > 0 && desc && desc->_dname_count > 0) { 637238106Sdes int count = (int)desc->_dname_count; 638238106Sdes int rdf = 0; 639238106Sdes size_t len; 640238106Sdes size_t oldpos; 641238106Sdes /* skip first part. */ 642238106Sdes while(pkt_len > 0 && count) { 643238106Sdes switch(desc->_wireformat[rdf]) { 644238106Sdes case LDNS_RDF_TYPE_DNAME: 645238106Sdes /* decompress every domain name */ 646238106Sdes oldpos = ldns_buffer_position(pkt); 647238106Sdes if((len = pkt_dname_len(pkt)) == 0) 648238106Sdes return 0; /* malformed dname */ 649238106Sdes if(ldns_buffer_position(pkt)-oldpos > pkt_len) 650238106Sdes return 0; /* dname exceeds rdata */ 651238106Sdes pkt_len -= ldns_buffer_position(pkt)-oldpos; 652238106Sdes rr->size += len; 653238106Sdes count--; 654238106Sdes len = 0; 655238106Sdes break; 656238106Sdes case LDNS_RDF_TYPE_STR: 657249141Sdes if(pkt_len < 1) { 658249141Sdes /* NOTREACHED, due to 'while(>0)' */ 659238106Sdes return 0; /* len byte exceeds rdata */ 660249141Sdes } 661238106Sdes len = ldns_buffer_current(pkt)[0] + 1; 662238106Sdes break; 663238106Sdes default: 664238106Sdes len = get_rdf_size(desc->_wireformat[rdf]); 665238106Sdes } 666238106Sdes if(len) { 667238106Sdes if(pkt_len < len) 668238106Sdes return 0; /* exceeds rdata */ 669238106Sdes pkt_len -= len; 670238106Sdes ldns_buffer_skip(pkt, (ssize_t)len); 671238106Sdes rr->size += len; 672238106Sdes } 673238106Sdes rdf++; 674238106Sdes } 675238106Sdes } 676238106Sdes /* remaining rdata */ 677238106Sdes rr->size += pkt_len; 678238106Sdes ldns_buffer_skip(pkt, (ssize_t)pkt_len); 679238106Sdes return 1; 680238106Sdes} 681238106Sdes 682238106Sdes/** skip rr ttl and rdata */ 683238106Sdesstatic int 684238106Sdesskip_ttl_rdata(ldns_buffer* pkt) 685238106Sdes{ 686238106Sdes uint16_t rdatalen; 687238106Sdes if(ldns_buffer_remaining(pkt) < 6) /* ttl + rdatalen */ 688238106Sdes return 0; 689238106Sdes ldns_buffer_skip(pkt, 4); /* ttl */ 690238106Sdes rdatalen = ldns_buffer_read_u16(pkt); 691238106Sdes if(ldns_buffer_remaining(pkt) < rdatalen) 692238106Sdes return 0; 693238106Sdes ldns_buffer_skip(pkt, (ssize_t)rdatalen); 694238106Sdes return 1; 695238106Sdes} 696238106Sdes 697238106Sdes/** see if RRSIG is a duplicate of another */ 698238106Sdesstatic int 699238106Sdessig_is_double(ldns_buffer* pkt, struct rrset_parse* rrset, uint8_t* ttldata) 700238106Sdes{ 701238106Sdes uint16_t rlen, siglen; 702238106Sdes size_t pos = ldns_buffer_position(pkt); 703238106Sdes struct rr_parse* sig; 704238106Sdes if(ldns_buffer_remaining(pkt) < 6) 705238106Sdes return 0; 706238106Sdes ldns_buffer_skip(pkt, 4); /* ttl */ 707238106Sdes rlen = ldns_buffer_read_u16(pkt); 708238106Sdes if(ldns_buffer_remaining(pkt) < rlen) { 709238106Sdes ldns_buffer_set_position(pkt, pos); 710238106Sdes return 0; 711238106Sdes } 712238106Sdes ldns_buffer_set_position(pkt, pos); 713238106Sdes 714238106Sdes sig = rrset->rrsig_first; 715238106Sdes while(sig) { 716238106Sdes /* check if rdatalen is same */ 717238106Sdes memmove(&siglen, sig->ttl_data+4, sizeof(siglen)); 718238106Sdes siglen = ntohs(siglen); 719238106Sdes /* checks if data in packet is exactly the same, this means 720238106Sdes * also dname in rdata is the same, but rrsig is not allowed 721238106Sdes * to have compressed dnames anyway. If it is compressed anyway 722238106Sdes * it will lead to duplicate rrs for qtype=RRSIG. (or ANY). 723238106Sdes * 724238106Sdes * Cannot use sig->size because size of the other one is not 725238106Sdes * calculated yet. 726238106Sdes */ 727238106Sdes if(siglen == rlen) { 728238106Sdes if(siglen>0 && memcmp(sig->ttl_data+6, ttldata+6, 729238106Sdes siglen) == 0) { 730238106Sdes /* same! */ 731238106Sdes return 1; 732238106Sdes } 733238106Sdes } 734238106Sdes sig = sig->next; 735238106Sdes } 736238106Sdes return 0; 737238106Sdes} 738238106Sdes 739238106Sdes/** Add rr (from packet here) to rrset, skips rr */ 740238106Sdesstatic int 741238106Sdesadd_rr_to_rrset(struct rrset_parse* rrset, ldns_buffer* pkt, 742238106Sdes struct msg_parse* msg, struct regional* region, 743238106Sdes ldns_pkt_section section, uint16_t type) 744238106Sdes{ 745238106Sdes struct rr_parse* rr; 746238106Sdes /* check section of rrset. */ 747238106Sdes if(rrset->section != section && type != LDNS_RR_TYPE_RRSIG && 748238106Sdes rrset->type != LDNS_RR_TYPE_RRSIG) { 749238106Sdes /* silently drop it - we drop the last part, since 750238106Sdes * trust in rr data depends on the section it is in. 751238106Sdes * the less trustworthy part is discarded. 752238106Sdes * also the last part is more likely to be incomplete. 753238106Sdes * RFC 2181: must put RRset only once in response. */ 754238106Sdes /* 755238106Sdes verbose(VERB_QUERY, "Packet contains rrset data in " 756238106Sdes "multiple sections, dropped last part."); 757238106Sdes log_buf(VERB_QUERY, "packet was", pkt); 758238106Sdes */ 759238106Sdes /* forwards */ 760238106Sdes if(!skip_ttl_rdata(pkt)) 761238106Sdes return LDNS_RCODE_FORMERR; 762238106Sdes return 0; 763238106Sdes } 764238106Sdes 765238106Sdes if( (msg->qtype == LDNS_RR_TYPE_RRSIG || 766238106Sdes msg->qtype == LDNS_RR_TYPE_ANY) 767238106Sdes && sig_is_double(pkt, rrset, ldns_buffer_current(pkt))) { 768238106Sdes if(!skip_ttl_rdata(pkt)) 769238106Sdes return LDNS_RCODE_FORMERR; 770238106Sdes return 0; 771238106Sdes } 772238106Sdes 773238106Sdes /* create rr */ 774238106Sdes if(!(rr = (struct rr_parse*)regional_alloc(region, sizeof(*rr)))) 775238106Sdes return LDNS_RCODE_SERVFAIL; 776238106Sdes rr->outside_packet = 0; 777238106Sdes rr->ttl_data = ldns_buffer_current(pkt); 778238106Sdes rr->next = 0; 779238106Sdes if(type == LDNS_RR_TYPE_RRSIG && rrset->type != LDNS_RR_TYPE_RRSIG) { 780238106Sdes if(rrset->rrsig_last) 781238106Sdes rrset->rrsig_last->next = rr; 782238106Sdes else rrset->rrsig_first = rr; 783238106Sdes rrset->rrsig_last = rr; 784238106Sdes rrset->rrsig_count++; 785238106Sdes } else { 786238106Sdes if(rrset->rr_last) 787238106Sdes rrset->rr_last->next = rr; 788238106Sdes else rrset->rr_first = rr; 789238106Sdes rrset->rr_last = rr; 790238106Sdes rrset->rr_count++; 791238106Sdes } 792238106Sdes 793238106Sdes /* calc decompressed size */ 794238106Sdes if(!calc_size(pkt, type, rr)) 795238106Sdes return LDNS_RCODE_FORMERR; 796238106Sdes rrset->size += rr->size; 797238106Sdes 798238106Sdes return 0; 799238106Sdes} 800238106Sdes 801238106Sdes/** 802238106Sdes * Parse packet RR section, for answer, authority and additional sections. 803238106Sdes * @param pkt: packet, position at call must be at start of section. 804238106Sdes * at end position is after section. 805238106Sdes * @param msg: store results here. 806238106Sdes * @param region: how to alloc results. 807238106Sdes * @param section: section enum. 808238106Sdes * @param num_rrs: how many rrs are in the section. 809238106Sdes * @param num_rrsets: returns number of rrsets in the section. 810238106Sdes * @return: 0 if OK, or rcode on error. 811238106Sdes */ 812238106Sdesstatic int 813238106Sdesparse_section(ldns_buffer* pkt, struct msg_parse* msg, 814238106Sdes struct regional* region, ldns_pkt_section section, 815238106Sdes uint16_t num_rrs, size_t* num_rrsets) 816238106Sdes{ 817238106Sdes uint16_t i; 818238106Sdes uint8_t* dname, *prev_dname_f = NULL, *prev_dname_l = NULL; 819238106Sdes size_t dnamelen, prev_dnamelen = 0; 820238106Sdes uint16_t type, prev_type = 0; 821238106Sdes uint16_t dclass, prev_dclass = 0; 822238106Sdes uint32_t rrset_flags = 0; 823238106Sdes hashvalue_t hash = 0; 824238106Sdes struct rrset_parse* rrset = NULL; 825238106Sdes int r; 826238106Sdes 827238106Sdes if(num_rrs == 0) 828238106Sdes return 0; 829238106Sdes if(ldns_buffer_remaining(pkt) <= 0) 830238106Sdes return LDNS_RCODE_FORMERR; 831238106Sdes for(i=0; i<num_rrs; i++) { 832238106Sdes /* parse this RR. */ 833238106Sdes dname = ldns_buffer_current(pkt); 834238106Sdes if((dnamelen = pkt_dname_len(pkt)) == 0) 835238106Sdes return LDNS_RCODE_FORMERR; 836238106Sdes if(ldns_buffer_remaining(pkt) < 10) /* type, class, ttl, len */ 837238106Sdes return LDNS_RCODE_FORMERR; 838238106Sdes type = ldns_buffer_read_u16(pkt); 839238106Sdes ldns_buffer_read(pkt, &dclass, sizeof(dclass)); 840238106Sdes 841238106Sdes if(0) { /* debug show what is being parsed. */ 842238106Sdes if(type == LDNS_RR_TYPE_RRSIG) { 843238106Sdes uint16_t t; 844238106Sdes if(pkt_rrsig_covered(pkt, 845238106Sdes ldns_buffer_current(pkt), &t)) 846238106Sdes fprintf(stderr, "parse of %s(%d) [%s(%d)]", 847238106Sdes ldns_rr_descript(type)? 848238106Sdes ldns_rr_descript(type)->_name: "??", 849238106Sdes (int)type, 850238106Sdes ldns_rr_descript(t)? 851238106Sdes ldns_rr_descript(t)->_name: "??", 852238106Sdes (int)t); 853238106Sdes } else 854238106Sdes fprintf(stderr, "parse of %s(%d)", 855238106Sdes ldns_rr_descript(type)? 856238106Sdes ldns_rr_descript(type)->_name: "??", 857238106Sdes (int)type); 858238106Sdes fprintf(stderr, " %s(%d) ", 859238106Sdes ldns_lookup_by_id(ldns_rr_classes, 860238106Sdes (int)ntohs(dclass))?ldns_lookup_by_id( 861238106Sdes ldns_rr_classes, (int)ntohs(dclass))->name: 862238106Sdes "??", (int)ntohs(dclass)); 863238106Sdes dname_print(stderr, pkt, dname); 864238106Sdes fprintf(stderr, "\n"); 865238106Sdes } 866238106Sdes 867238106Sdes /* see if it is part of an existing RR set */ 868238106Sdes if(!find_rrset(msg, pkt, dname, dnamelen, type, dclass, &hash, 869238106Sdes &rrset_flags, &prev_dname_f, &prev_dname_l, 870238106Sdes &prev_dnamelen, &prev_type, &prev_dclass, &rrset, 871238106Sdes section, region)) 872238106Sdes return LDNS_RCODE_SERVFAIL; 873238106Sdes if(!rrset) { 874238106Sdes /* it is a new RR set. hash&flags already calculated.*/ 875238106Sdes (*num_rrsets)++; 876238106Sdes rrset = new_rrset(msg, dname, dnamelen, type, dclass, 877238106Sdes hash, rrset_flags, section, region); 878238106Sdes if(!rrset) 879238106Sdes return LDNS_RCODE_SERVFAIL; 880238106Sdes } 881238106Sdes else if(0) { 882238106Sdes fprintf(stderr, "is part of existing: "); 883238106Sdes dname_print(stderr, pkt, rrset->dname); 884238106Sdes fprintf(stderr, " type %s(%d)\n", 885238106Sdes ldns_rr_descript(rrset->type)? 886238106Sdes ldns_rr_descript(rrset->type)->_name: "??", 887238106Sdes (int)rrset->type); 888238106Sdes } 889238106Sdes /* add to rrset. */ 890238106Sdes if((r=add_rr_to_rrset(rrset, pkt, msg, region, section, 891238106Sdes type)) != 0) 892238106Sdes return r; 893238106Sdes } 894238106Sdes return 0; 895238106Sdes} 896238106Sdes 897238106Sdesint 898238106Sdesparse_packet(ldns_buffer* pkt, struct msg_parse* msg, struct regional* region) 899238106Sdes{ 900238106Sdes int ret; 901238106Sdes if(ldns_buffer_remaining(pkt) < LDNS_HEADER_SIZE) 902238106Sdes return LDNS_RCODE_FORMERR; 903238106Sdes /* read the header */ 904238106Sdes ldns_buffer_read(pkt, &msg->id, sizeof(uint16_t)); 905238106Sdes msg->flags = ldns_buffer_read_u16(pkt); 906238106Sdes msg->qdcount = ldns_buffer_read_u16(pkt); 907238106Sdes msg->ancount = ldns_buffer_read_u16(pkt); 908238106Sdes msg->nscount = ldns_buffer_read_u16(pkt); 909238106Sdes msg->arcount = ldns_buffer_read_u16(pkt); 910238106Sdes if(msg->qdcount > 1) 911238106Sdes return LDNS_RCODE_FORMERR; 912238106Sdes if((ret = parse_query_section(pkt, msg)) != 0) 913238106Sdes return ret; 914238106Sdes if((ret = parse_section(pkt, msg, region, LDNS_SECTION_ANSWER, 915238106Sdes msg->ancount, &msg->an_rrsets)) != 0) 916238106Sdes return ret; 917238106Sdes if((ret = parse_section(pkt, msg, region, LDNS_SECTION_AUTHORITY, 918238106Sdes msg->nscount, &msg->ns_rrsets)) != 0) 919238106Sdes return ret; 920238106Sdes if(ldns_buffer_remaining(pkt) == 0 && msg->arcount == 1) { 921238106Sdes /* BIND accepts leniently that an EDNS record is missing. 922238106Sdes * so, we do too. */ 923238106Sdes } else if((ret = parse_section(pkt, msg, region, 924238106Sdes LDNS_SECTION_ADDITIONAL, msg->arcount, &msg->ar_rrsets)) != 0) 925238106Sdes return ret; 926238106Sdes /* if(ldns_buffer_remaining(pkt) > 0) { */ 927238106Sdes /* there is spurious data at end of packet. ignore */ 928238106Sdes /* } */ 929238106Sdes msg->rrset_count = msg->an_rrsets + msg->ns_rrsets + msg->ar_rrsets; 930238106Sdes return 0; 931238106Sdes} 932238106Sdes 933238106Sdesint 934238106Sdesparse_extract_edns(struct msg_parse* msg, struct edns_data* edns) 935238106Sdes{ 936238106Sdes struct rrset_parse* rrset = msg->rrset_first; 937238106Sdes struct rrset_parse* prev = 0; 938238106Sdes struct rrset_parse* found = 0; 939238106Sdes struct rrset_parse* found_prev = 0; 940238106Sdes /* since the class encodes the UDP size, we cannot use hash table to 941238106Sdes * find the EDNS OPT record. Scan the packet. */ 942238106Sdes while(rrset) { 943238106Sdes if(rrset->type == LDNS_RR_TYPE_OPT) { 944238106Sdes /* only one OPT RR allowed. */ 945238106Sdes if(found) return LDNS_RCODE_FORMERR; 946238106Sdes /* found it! */ 947238106Sdes found_prev = prev; 948238106Sdes found = rrset; 949238106Sdes } 950238106Sdes prev = rrset; 951238106Sdes rrset = rrset->rrset_all_next; 952238106Sdes } 953238106Sdes if(!found) { 954238106Sdes memset(edns, 0, sizeof(*edns)); 955238106Sdes edns->udp_size = 512; 956238106Sdes return 0; 957238106Sdes } 958238106Sdes /* check the found RRset */ 959238106Sdes /* most lenient check possible. ignore dname, use last opt */ 960238106Sdes if(found->section != LDNS_SECTION_ADDITIONAL) 961238106Sdes return LDNS_RCODE_FORMERR; 962238106Sdes if(found->rr_count == 0) 963238106Sdes return LDNS_RCODE_FORMERR; 964238106Sdes if(0) { /* strict checking of dname and RRcount */ 965238106Sdes if(found->dname_len != 1 || !found->dname 966238106Sdes || found->dname[0] != 0) return LDNS_RCODE_FORMERR; 967238106Sdes if(found->rr_count != 1) return LDNS_RCODE_FORMERR; 968238106Sdes } 969238106Sdes log_assert(found->rr_first && found->rr_last); 970238106Sdes 971238106Sdes /* remove from packet */ 972238106Sdes if(found_prev) found_prev->rrset_all_next = found->rrset_all_next; 973238106Sdes else msg->rrset_first = found->rrset_all_next; 974238106Sdes if(found == msg->rrset_last) 975238106Sdes msg->rrset_last = found_prev; 976238106Sdes msg->arcount --; 977238106Sdes msg->ar_rrsets --; 978238106Sdes msg->rrset_count --; 979238106Sdes 980238106Sdes /* take the data ! */ 981238106Sdes edns->edns_present = 1; 982238106Sdes edns->ext_rcode = found->rr_last->ttl_data[0]; 983238106Sdes edns->edns_version = found->rr_last->ttl_data[1]; 984238106Sdes edns->bits = ldns_read_uint16(&found->rr_last->ttl_data[2]); 985238106Sdes edns->udp_size = ntohs(found->rrset_class); 986238106Sdes /* ignore rdata and rrsigs */ 987238106Sdes return 0; 988238106Sdes} 989238106Sdes 990238106Sdesint 991238106Sdesparse_edns_from_pkt(ldns_buffer* pkt, struct edns_data* edns) 992238106Sdes{ 993238106Sdes log_assert(LDNS_QDCOUNT(ldns_buffer_begin(pkt)) == 1); 994238106Sdes log_assert(LDNS_ANCOUNT(ldns_buffer_begin(pkt)) == 0); 995238106Sdes log_assert(LDNS_NSCOUNT(ldns_buffer_begin(pkt)) == 0); 996238106Sdes /* check edns section is present */ 997238106Sdes if(LDNS_ARCOUNT(ldns_buffer_begin(pkt)) > 1) { 998238106Sdes return LDNS_RCODE_FORMERR; 999238106Sdes } 1000238106Sdes if(LDNS_ARCOUNT(ldns_buffer_begin(pkt)) == 0) { 1001238106Sdes memset(edns, 0, sizeof(*edns)); 1002238106Sdes edns->udp_size = 512; 1003238106Sdes return 0; 1004238106Sdes } 1005238106Sdes /* domain name must be the root of length 1. */ 1006238106Sdes if(pkt_dname_len(pkt) != 1) 1007238106Sdes return LDNS_RCODE_FORMERR; 1008238106Sdes if(ldns_buffer_remaining(pkt) < 10) /* type, class, ttl, rdatalen */ 1009238106Sdes return LDNS_RCODE_FORMERR; 1010238106Sdes if(ldns_buffer_read_u16(pkt) != LDNS_RR_TYPE_OPT) 1011238106Sdes return LDNS_RCODE_FORMERR; 1012238106Sdes edns->edns_present = 1; 1013238106Sdes edns->udp_size = ldns_buffer_read_u16(pkt); /* class is udp size */ 1014238106Sdes edns->ext_rcode = ldns_buffer_read_u8(pkt); /* ttl used for bits */ 1015238106Sdes edns->edns_version = ldns_buffer_read_u8(pkt); 1016238106Sdes edns->bits = ldns_buffer_read_u16(pkt); 1017238106Sdes /* ignore rdata and rrsigs */ 1018238106Sdes return 0; 1019238106Sdes} 1020