Swiftdiff options
Diffstat (limited to '3rdParty/Unbound/src/src/util/data/msgparse.c')
| -rw-r--r-- | 3rdParty/Unbound/src/src/util/data/msgparse.c | 1018 |
1 files changed, 1018 insertions, 0 deletions
diff --git a/3rdParty/Unbound/src/src/util/data/msgparse.c b/3rdParty/Unbound/src/src/util/data/msgparse.c new file mode 100644 index 0000000..a03f543 --- /dev/null +++ b/3rdParty/Unbound/src/src/util/data/msgparse.c @@ -0,0 +1,1018 @@ +/* + * util/data/msgparse.c - parse wireformat DNS messages. + * + * Copyright (c) 2007, NLnet Labs. All rights reserved. + * + * This software is open source. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * + * Redistributions of source code must retain the above copyright notice, + * this list of conditions and the following disclaimer. + * + * Redistributions in binary form must reproduce the above copyright notice, + * this list of conditions and the following disclaimer in the documentation + * and/or other materials provided with the distribution. + * + * Neither the name of the NLNET LABS nor the names of its contributors may + * be used to endorse or promote products derived from this software without + * specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED + * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR + * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE + * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR + * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF + * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS + * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN + * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) + * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE + * POSSIBILITY OF SUCH DAMAGE. + */ +/** + * \file + * Routines for message parsing a packet buffer to a descriptive structure. + */ +#include "config.h" +#include <ldns/ldns.h> +#include "util/data/msgparse.h" +#include "util/net_help.h" +#include "util/data/dname.h" +#include "util/data/packed_rrset.h" +#include "util/storage/lookup3.h" +#include "util/regional.h" + +/** smart comparison of (compressed, valid) dnames from packet */ +static int +smart_compare(ldns_buffer* pkt, uint8_t* dnow, + uint8_t* dprfirst, uint8_t* dprlast) +{ + if(LABEL_IS_PTR(*dnow)) { + /* ptr points to a previous dname */ + uint8_t* p = ldns_buffer_at(pkt, PTR_OFFSET(dnow[0], dnow[1])); + if( p == dprfirst || p == dprlast ) + return 0; + /* prev dname is also a ptr, both ptrs are the same. */ + if(LABEL_IS_PTR(*dprlast) && + dprlast[0] == dnow[0] && dprlast[1] == dnow[1]) + return 0; + } + return dname_pkt_compare(pkt, dnow, dprlast); +} + +/** + * Allocate new rrset in region, fill with data. + */ +static struct rrset_parse* +new_rrset(struct msg_parse* msg, uint8_t* dname, size_t dnamelen, + uint16_t type, uint16_t dclass, hashvalue_t hash, + uint32_t rrset_flags, ldns_pkt_section section, + struct regional* region) +{ + struct rrset_parse* p = regional_alloc(region, sizeof(*p)); + if(!p) return NULL; + p->rrset_bucket_next = msg->hashtable[hash & (PARSE_TABLE_SIZE-1)]; + msg->hashtable[hash & (PARSE_TABLE_SIZE-1)] = p; + p->rrset_all_next = 0; + if(msg->rrset_last) + msg->rrset_last->rrset_all_next = p; + else msg->rrset_first = p; + msg->rrset_last = p; + p->hash = hash; + p->section = section; + p->dname = dname; + p->dname_len = dnamelen; + p->type = type; + p->rrset_class = dclass; + p->flags = rrset_flags; + p->rr_count = 0; + p->size = 0; + p->rr_first = 0; + p->rr_last = 0; + p->rrsig_count = 0; + p->rrsig_first = 0; + p->rrsig_last = 0; + return p; +} + +/** See if next rrset is nsec at zone apex */ +static int +nsec_at_apex(ldns_buffer* pkt) +{ + /* we are at ttl position in packet. */ + size_t pos = ldns_buffer_position(pkt); + uint16_t rdatalen; + if(ldns_buffer_remaining(pkt) < 7) /* ttl+len+root */ + return 0; /* eek! */ + ldns_buffer_skip(pkt, 4); /* ttl */; + rdatalen = ldns_buffer_read_u16(pkt); + if(ldns_buffer_remaining(pkt) < rdatalen) { + ldns_buffer_set_position(pkt, pos); + return 0; /* parse error happens later */ + } + /* must validate the nsec next domain name format */ + if(pkt_dname_len(pkt) == 0) { + ldns_buffer_set_position(pkt, pos); + return 0; /* parse error */ + } + + /* see if SOA bit is set. */ + if(ldns_buffer_position(pkt) < pos+4+rdatalen) { + /* nsec type bitmap contains items */ + uint8_t win, blen, bits; + /* need: windownum, bitmap len, firstbyte */ + if(ldns_buffer_position(pkt)+3 > pos+4+rdatalen) { + ldns_buffer_set_position(pkt, pos); + return 0; /* malformed nsec */ + } + win = ldns_buffer_read_u8(pkt); + blen = ldns_buffer_read_u8(pkt); + bits = ldns_buffer_read_u8(pkt); + /* 0window always first window. bitlen >=1 or parse + error really. bit 0x2 is SOA. */ + if(win == 0 && blen >= 1 && (bits & 0x02)) { + ldns_buffer_set_position(pkt, pos); + return 1; + } + } + + ldns_buffer_set_position(pkt, pos); + return 0; +} + +/** Calculate rrset flags */ +static uint32_t +pkt_rrset_flags(ldns_buffer* pkt, uint16_t type, ldns_pkt_section sec) +{ + uint32_t f = 0; + if(type == LDNS_RR_TYPE_NSEC && nsec_at_apex(pkt)) { + f |= PACKED_RRSET_NSEC_AT_APEX; + } else if(type == LDNS_RR_TYPE_SOA && sec == LDNS_SECTION_AUTHORITY) { + f |= PACKED_RRSET_SOA_NEG; + } + return f; +} + +hashvalue_t +pkt_hash_rrset(ldns_buffer* pkt, uint8_t* dname, uint16_t type, + uint16_t dclass, uint32_t rrset_flags) +{ + /* note this MUST be identical to rrset_key_hash in packed_rrset.c */ + /* this routine handles compressed names */ + hashvalue_t h = 0xab; + h = dname_pkt_hash(pkt, dname, h); + h = hashlittle(&type, sizeof(type), h); /* host order */ + h = hashlittle(&dclass, sizeof(dclass), h); /* netw order */ + h = hashlittle(&rrset_flags, sizeof(uint32_t), h); + return h; +} + +/** create partial dname hash for rrset hash */ +static hashvalue_t +pkt_hash_rrset_first(ldns_buffer* pkt, uint8_t* dname) +{ + /* works together with pkt_hash_rrset_rest */ + /* note this MUST be identical to rrset_key_hash in packed_rrset.c */ + /* this routine handles compressed names */ + hashvalue_t h = 0xab; + h = dname_pkt_hash(pkt, dname, h); + return h; +} + +/** create a rrset hash from a partial dname hash */ +static hashvalue_t +pkt_hash_rrset_rest(hashvalue_t dname_h, uint16_t type, uint16_t dclass, + uint32_t rrset_flags) +{ + /* works together with pkt_hash_rrset_first */ + /* note this MUST be identical to rrset_key_hash in packed_rrset.c */ + hashvalue_t h; + h = hashlittle(&type, sizeof(type), dname_h); /* host order */ + h = hashlittle(&dclass, sizeof(dclass), h); /* netw order */ + h = hashlittle(&rrset_flags, sizeof(uint32_t), h); + return h; +} + +/** compare rrset_parse with data */ +static int +rrset_parse_equals(struct rrset_parse* p, ldns_buffer* pkt, hashvalue_t h, + uint32_t rrset_flags, uint8_t* dname, size_t dnamelen, + uint16_t type, uint16_t dclass) +{ + if(p->hash == h && p->dname_len == dnamelen && p->type == type && + p->rrset_class == dclass && p->flags == rrset_flags && + dname_pkt_compare(pkt, dname, p->dname) == 0) + return 1; + return 0; +} + + +struct rrset_parse* +msgparse_hashtable_lookup(struct msg_parse* msg, ldns_buffer* pkt, + hashvalue_t h, uint32_t rrset_flags, uint8_t* dname, size_t dnamelen, + uint16_t type, uint16_t dclass) +{ + struct rrset_parse* p = msg->hashtable[h & (PARSE_TABLE_SIZE-1)]; + while(p) { + if(rrset_parse_equals(p, pkt, h, rrset_flags, dname, dnamelen, + type, dclass)) + return p; + p = p->rrset_bucket_next; + } + return NULL; +} + +/** return type networkformat that rrsig in packet covers */ +static int +pkt_rrsig_covered(ldns_buffer* pkt, uint8_t* here, uint16_t* type) +{ + size_t pos = ldns_buffer_position(pkt); + ldns_buffer_set_position(pkt, (size_t)(here-ldns_buffer_begin(pkt))); + /* ttl + len + size of small rrsig(rootlabel, no signature) */ + if(ldns_buffer_remaining(pkt) < 4+2+19) + return 0; + ldns_buffer_skip(pkt, 4); /* ttl */ + if(ldns_buffer_read_u16(pkt) < 19) /* too short */ { + ldns_buffer_set_position(pkt, pos); + return 0; + } + *type = ldns_buffer_read_u16(pkt); + ldns_buffer_set_position(pkt, pos); + return 1; +} + +/** true if covered type equals prevtype */ +static int +pkt_rrsig_covered_equals(ldns_buffer* pkt, uint8_t* here, uint16_t type) +{ + uint16_t t; + if(pkt_rrsig_covered(pkt, here, &t) && t == type) + return 1; + return 0; +} + +void +msgparse_bucket_remove(struct msg_parse* msg, struct rrset_parse* rrset) +{ + struct rrset_parse** p; + p = &msg->hashtable[ rrset->hash & (PARSE_TABLE_SIZE-1) ]; + while(*p) { + if(*p == rrset) { + *p = rrset->rrset_bucket_next; + return; + } + p = &( (*p)->rrset_bucket_next ); + } +} + +/** change section of rrset from previous to current section */ +static void +change_section(struct msg_parse* msg, struct rrset_parse* rrset, + ldns_pkt_section section) +{ + struct rrset_parse *p, *prev; + /* remove from list */ + if(section == rrset->section) + return; + p = msg->rrset_first; + prev = 0; + while(p) { + if(p == rrset) { + if(prev) prev->rrset_all_next = p->rrset_all_next; + else msg->rrset_first = p->rrset_all_next; + if(msg->rrset_last == rrset) + msg->rrset_last = prev; + break; + } + prev = p; + p = p->rrset_all_next; + } + /* remove from count */ + switch(rrset->section) { + case LDNS_SECTION_ANSWER: msg->an_rrsets--; break; + case LDNS_SECTION_AUTHORITY: msg->ns_rrsets--; break; + case LDNS_SECTION_ADDITIONAL: msg->ar_rrsets--; break; + default: log_assert(0); + } + /* insert at end of list */ + rrset->rrset_all_next = 0; + if(msg->rrset_last) + msg->rrset_last->rrset_all_next = rrset; + else msg->rrset_first = rrset; + msg->rrset_last = rrset; + /* up count of new section */ + switch(section) { + case LDNS_SECTION_AUTHORITY: msg->ns_rrsets++; break; + case LDNS_SECTION_ADDITIONAL: msg->ar_rrsets++; break; + default: log_assert(0); + } + rrset->section = section; +} + +/** see if rrset of type RRSIG contains sig over given type */ +static int +rrset_has_sigover(ldns_buffer* pkt, struct rrset_parse* rrset, uint16_t type, + int* hasother) +{ + int res = 0; + struct rr_parse* rr = rrset->rr_first; + log_assert( rrset->type == LDNS_RR_TYPE_RRSIG ); + while(rr) { + if(pkt_rrsig_covered_equals(pkt, rr->ttl_data, type)) + res = 1; + else *hasother = 1; + rr = rr->next; + } + return res; +} + +/** move rrsigs from sigset to dataset */ +static int +moveover_rrsigs(ldns_buffer* pkt, struct regional* region, + struct rrset_parse* sigset, struct rrset_parse* dataset, int duplicate) +{ + struct rr_parse* sig = sigset->rr_first; + struct rr_parse* prev = NULL; + struct rr_parse* insert; + struct rr_parse* nextsig; + while(sig) { + nextsig = sig->next; + if(pkt_rrsig_covered_equals(pkt, sig->ttl_data, + dataset->type)) { + if(duplicate) { + /* new */ + insert = (struct rr_parse*)regional_alloc( + region, sizeof(struct rr_parse)); + if(!insert) return 0; + insert->outside_packet = 0; + insert->ttl_data = sig->ttl_data; + insert->size = sig->size; + /* prev not used */ + } else { + /* remove from sigset */ + if(prev) prev->next = sig->next; + else sigset->rr_first = sig->next; + if(sigset->rr_last == sig) + sigset->rr_last = prev; + sigset->rr_count--; + sigset->size -= sig->size; + insert = sig; + /* prev not changed */ + } + /* add to dataset */ + dataset->rrsig_count++; + insert->next = 0; + if(dataset->rrsig_last) + dataset->rrsig_last->next = insert; + else dataset->rrsig_first = insert; + dataset->rrsig_last = insert; + dataset->size += insert->size; + } else { + prev = sig; + } + sig = nextsig; + } + return 1; +} + +/** change an rrsig rrset for use as data rrset */ +static struct rrset_parse* +change_rrsig_rrset(struct rrset_parse* sigset, struct msg_parse* msg, + ldns_buffer* pkt, uint16_t datatype, uint32_t rrset_flags, + int hasother, ldns_pkt_section section, struct regional* region) +{ + struct rrset_parse* dataset = sigset; + hashvalue_t hash = pkt_hash_rrset(pkt, sigset->dname, datatype, + sigset->rrset_class, rrset_flags); + log_assert( sigset->type == LDNS_RR_TYPE_RRSIG ); + log_assert( datatype != LDNS_RR_TYPE_RRSIG ); + if(hasother) { + /* need to make new rrset to hold data type */ + dataset = new_rrset(msg, sigset->dname, sigset->dname_len, + datatype, sigset->rrset_class, hash, rrset_flags, + section, region); + if(!dataset) + return NULL; + switch(section) { + case LDNS_SECTION_ANSWER: msg->an_rrsets++; break; + case LDNS_SECTION_AUTHORITY: msg->ns_rrsets++; break; + case LDNS_SECTION_ADDITIONAL: msg->ar_rrsets++; break; + default: log_assert(0); + } + if(!moveover_rrsigs(pkt, region, sigset, dataset, + msg->qtype == LDNS_RR_TYPE_RRSIG || + (msg->qtype == LDNS_RR_TYPE_ANY && + section != LDNS_SECTION_ANSWER) )) + return NULL; + return dataset; + } + /* changeover the type of the rrset to data set */ + msgparse_bucket_remove(msg, dataset); + /* insert into new hash bucket */ + dataset->rrset_bucket_next = msg->hashtable[hash&(PARSE_TABLE_SIZE-1)]; + msg->hashtable[hash&(PARSE_TABLE_SIZE-1)] = dataset; + dataset->hash = hash; + /* use section of data item for result */ + change_section(msg, dataset, section); + dataset->type = datatype; + dataset->flags = rrset_flags; + dataset->rrsig_count += dataset->rr_count; + dataset->rr_count = 0; + /* move sigs to end of siglist */ + if(dataset->rrsig_last) + dataset->rrsig_last->next = dataset->rr_first; + else dataset->rrsig_first = dataset->rr_first; + dataset->rrsig_last = dataset->rr_last; + dataset->rr_first = 0; + dataset->rr_last = 0; + return dataset; +} + +/** Find rrset. If equal to previous it is fast. hash if not so. + * @param msg: the message with hash table. + * @param pkt: the packet in wireformat (needed for compression ptrs). + * @param dname: pointer to start of dname (compressed) in packet. + * @param dnamelen: uncompressed wirefmt length of dname. + * @param type: type of current rr. + * @param dclass: class of current rr. + * @param hash: hash value is returned if the rrset could not be found. + * @param rrset_flags: is returned if the rrset could not be found. + * @param prev_dname_first: dname of last seen RR. First seen dname. + * @param prev_dname_last: dname of last seen RR. Last seen dname. + * @param prev_dnamelen: dname len of last seen RR. + * @param prev_type: type of last seen RR. + * @param prev_dclass: class of last seen RR. + * @param rrset_prev: last seen RRset. + * @param section: the current section in the packet. + * @param region: used to allocate temporary parsing data. + * @return 0 on out of memory. + */ +static int +find_rrset(struct msg_parse* msg, ldns_buffer* pkt, uint8_t* dname, + size_t dnamelen, uint16_t type, uint16_t dclass, hashvalue_t* hash, + uint32_t* rrset_flags, + uint8_t** prev_dname_first, uint8_t** prev_dname_last, + size_t* prev_dnamelen, uint16_t* prev_type, + uint16_t* prev_dclass, struct rrset_parse** rrset_prev, + ldns_pkt_section section, struct regional* region) +{ + hashvalue_t dname_h = pkt_hash_rrset_first(pkt, dname); + uint16_t covtype; + if(*rrset_prev) { + /* check if equal to previous item */ + if(type == *prev_type && dclass == *prev_dclass && + dnamelen == *prev_dnamelen && + smart_compare(pkt, dname, *prev_dname_first, + *prev_dname_last) == 0 && + type != LDNS_RR_TYPE_RRSIG) { + /* same as previous */ + *prev_dname_last = dname; + return 1; + } + /* check if rrsig over previous item */ + if(type == LDNS_RR_TYPE_RRSIG && dclass == *prev_dclass && + pkt_rrsig_covered_equals(pkt, ldns_buffer_current(pkt), + *prev_type) && + smart_compare(pkt, dname, *prev_dname_first, + *prev_dname_last) == 0) { + /* covers previous */ + *prev_dname_last = dname; + return 1; + } + } + /* find by hashing and lookup in hashtable */ + *rrset_flags = pkt_rrset_flags(pkt, type, section); + + /* if rrsig - try to lookup matching data set first */ + if(type == LDNS_RR_TYPE_RRSIG && pkt_rrsig_covered(pkt, + ldns_buffer_current(pkt), &covtype)) { + *hash = pkt_hash_rrset_rest(dname_h, covtype, dclass, + *rrset_flags); + *rrset_prev = msgparse_hashtable_lookup(msg, pkt, *hash, + *rrset_flags, dname, dnamelen, covtype, dclass); + if(!*rrset_prev && covtype == LDNS_RR_TYPE_NSEC) { + /* if NSEC try with NSEC apex bit twiddled */ + *rrset_flags ^= PACKED_RRSET_NSEC_AT_APEX; + *hash = pkt_hash_rrset_rest(dname_h, covtype, dclass, + *rrset_flags); + *rrset_prev = msgparse_hashtable_lookup(msg, pkt, + *hash, *rrset_flags, dname, dnamelen, covtype, + dclass); + if(!*rrset_prev) /* untwiddle if not found */ + *rrset_flags ^= PACKED_RRSET_NSEC_AT_APEX; + } + if(!*rrset_prev && covtype == LDNS_RR_TYPE_SOA) { + /* if SOA try with SOA neg flag twiddled */ + *rrset_flags ^= PACKED_RRSET_SOA_NEG; + *hash = pkt_hash_rrset_rest(dname_h, covtype, dclass, + *rrset_flags); + *rrset_prev = msgparse_hashtable_lookup(msg, pkt, + *hash, *rrset_flags, dname, dnamelen, covtype, + dclass); + if(!*rrset_prev) /* untwiddle if not found */ + *rrset_flags ^= PACKED_RRSET_SOA_NEG; + } + if(*rrset_prev) { + *prev_dname_first = (*rrset_prev)->dname; + *prev_dname_last = dname; + *prev_dnamelen = dnamelen; + *prev_type = covtype; + *prev_dclass = dclass; + return 1; + } + } + if(type != LDNS_RR_TYPE_RRSIG) { + int hasother = 0; + /* find matching rrsig */ + *hash = pkt_hash_rrset_rest(dname_h, LDNS_RR_TYPE_RRSIG, + dclass, 0); + *rrset_prev = msgparse_hashtable_lookup(msg, pkt, *hash, + 0, dname, dnamelen, LDNS_RR_TYPE_RRSIG, + dclass); + if(*rrset_prev && rrset_has_sigover(pkt, *rrset_prev, type, + &hasother)) { + /* yes! */ + *prev_dname_first = (*rrset_prev)->dname; + *prev_dname_last = dname; + *prev_dnamelen = dnamelen; + *prev_type = type; + *prev_dclass = dclass; + *rrset_prev = change_rrsig_rrset(*rrset_prev, msg, + pkt, type, *rrset_flags, hasother, section, + region); + if(!*rrset_prev) return 0; + return 1; + } + } + + *hash = pkt_hash_rrset_rest(dname_h, type, dclass, *rrset_flags); + *rrset_prev = msgparse_hashtable_lookup(msg, pkt, *hash, *rrset_flags, + dname, dnamelen, type, dclass); + if(*rrset_prev) + *prev_dname_first = (*rrset_prev)->dname; + else *prev_dname_first = dname; + *prev_dname_last = dname; + *prev_dnamelen = dnamelen; + *prev_type = type; + *prev_dclass = dclass; + return 1; +} + +/** + * Parse query section. + * @param pkt: packet, position at call must be at start of query section. + * at end position is after query section. + * @param msg: store results here. + * @return: 0 if OK, or rcode on error. + */ +static int +parse_query_section(ldns_buffer* pkt, struct msg_parse* msg) +{ + if(msg->qdcount == 0) + return 0; + if(msg->qdcount > 1) + return LDNS_RCODE_FORMERR; + log_assert(msg->qdcount == 1); + if(ldns_buffer_remaining(pkt) <= 0) + return LDNS_RCODE_FORMERR; + msg->qname = ldns_buffer_current(pkt); + if((msg->qname_len = pkt_dname_len(pkt)) == 0) + return LDNS_RCODE_FORMERR; + if(ldns_buffer_remaining(pkt) < sizeof(uint16_t)*2) + return LDNS_RCODE_FORMERR; + msg->qtype = ldns_buffer_read_u16(pkt); + msg->qclass = ldns_buffer_read_u16(pkt); + return 0; +} + +size_t +get_rdf_size(ldns_rdf_type rdf) +{ + switch(rdf) { + case LDNS_RDF_TYPE_CLASS: + case LDNS_RDF_TYPE_ALG: + case LDNS_RDF_TYPE_INT8: + return 1; + break; + case LDNS_RDF_TYPE_INT16: + case LDNS_RDF_TYPE_TYPE: + case LDNS_RDF_TYPE_CERT_ALG: + return 2; + break; + case LDNS_RDF_TYPE_INT32: + case LDNS_RDF_TYPE_TIME: + case LDNS_RDF_TYPE_A: + case LDNS_RDF_TYPE_PERIOD: + return 4; + break; + case LDNS_RDF_TYPE_TSIGTIME: + return 6; + break; + case LDNS_RDF_TYPE_AAAA: + return 16; + break; + default: + log_assert(false); /* add type above */ + /* only types that appear before a domain * + * name are needed. rest is simply copied. */ + } + return 0; +} + +/** calculate the size of one rr */ +static int +calc_size(ldns_buffer* pkt, uint16_t type, struct rr_parse* rr) +{ + const ldns_rr_descriptor* desc; + uint16_t pkt_len; /* length of rr inside the packet */ + rr->size = sizeof(uint16_t); /* the rdatalen */ + ldns_buffer_skip(pkt, 4); /* skip ttl */ + pkt_len = ldns_buffer_read_u16(pkt); + if(ldns_buffer_remaining(pkt) < pkt_len) + return 0; + desc = ldns_rr_descript(type); + if(pkt_len > 0 && desc && desc->_dname_count > 0) { + int count = (int)desc->_dname_count; + int rdf = 0; + size_t len; + size_t oldpos; + /* skip first part. */ + while(pkt_len > 0 && count) { + switch(desc->_wireformat[rdf]) { + case LDNS_RDF_TYPE_DNAME: + /* decompress every domain name */ + oldpos = ldns_buffer_position(pkt); + if((len = pkt_dname_len(pkt)) == 0) + return 0; /* malformed dname */ + if(ldns_buffer_position(pkt)-oldpos > pkt_len) + return 0; /* dname exceeds rdata */ + pkt_len -= ldns_buffer_position(pkt)-oldpos; + rr->size += len; + count--; + len = 0; + break; + case LDNS_RDF_TYPE_STR: + if(pkt_len < 1) + return 0; /* len byte exceeds rdata */ + len = ldns_buffer_current(pkt)[0] + 1; + break; + default: + len = get_rdf_size(desc->_wireformat[rdf]); + } + if(len) { + if(pkt_len < len) + return 0; /* exceeds rdata */ + pkt_len -= len; + ldns_buffer_skip(pkt, (ssize_t)len); + rr->size += len; + } + rdf++; + } + } + /* remaining rdata */ + rr->size += pkt_len; + ldns_buffer_skip(pkt, (ssize_t)pkt_len); + return 1; +} + +/** skip rr ttl and rdata */ +static int +skip_ttl_rdata(ldns_buffer* pkt) +{ + uint16_t rdatalen; + if(ldns_buffer_remaining(pkt) < 6) /* ttl + rdatalen */ + return 0; + ldns_buffer_skip(pkt, 4); /* ttl */ + rdatalen = ldns_buffer_read_u16(pkt); + if(ldns_buffer_remaining(pkt) < rdatalen) + return 0; + ldns_buffer_skip(pkt, (ssize_t)rdatalen); + return 1; +} + +/** see if RRSIG is a duplicate of another */ +static int +sig_is_double(ldns_buffer* pkt, struct rrset_parse* rrset, uint8_t* ttldata) +{ + uint16_t rlen, siglen; + size_t pos = ldns_buffer_position(pkt); + struct rr_parse* sig; + if(ldns_buffer_remaining(pkt) < 6) + return 0; + ldns_buffer_skip(pkt, 4); /* ttl */ + rlen = ldns_buffer_read_u16(pkt); + if(ldns_buffer_remaining(pkt) < rlen) { + ldns_buffer_set_position(pkt, pos); + return 0; + } + ldns_buffer_set_position(pkt, pos); + + sig = rrset->rrsig_first; + while(sig) { + /* check if rdatalen is same */ + memmove(&siglen, sig->ttl_data+4, sizeof(siglen)); + siglen = ntohs(siglen); + /* checks if data in packet is exactly the same, this means + * also dname in rdata is the same, but rrsig is not allowed + * to have compressed dnames anyway. If it is compressed anyway + * it will lead to duplicate rrs for qtype=RRSIG. (or ANY). + * + * Cannot use sig->size because size of the other one is not + * calculated yet. + */ + if(siglen == rlen) { + if(siglen>0 && memcmp(sig->ttl_data+6, ttldata+6, + siglen) == 0) { + /* same! */ + return 1; + } + } + sig = sig->next; + } + return 0; +} + +/** Add rr (from packet here) to rrset, skips rr */ +static int +add_rr_to_rrset(struct rrset_parse* rrset, ldns_buffer* pkt, + struct msg_parse* msg, struct regional* region, + ldns_pkt_section section, uint16_t type) +{ + struct rr_parse* rr; + /* check section of rrset. */ + if(rrset->section != section && type != LDNS_RR_TYPE_RRSIG && + rrset->type != LDNS_RR_TYPE_RRSIG) { + /* silently drop it - we drop the last part, since + * trust in rr data depends on the section it is in. + * the less trustworthy part is discarded. + * also the last part is more likely to be incomplete. + * RFC 2181: must put RRset only once in response. */ + /* + verbose(VERB_QUERY, "Packet contains rrset data in " + "multiple sections, dropped last part."); + log_buf(VERB_QUERY, "packet was", pkt); + */ + /* forwards */ + if(!skip_ttl_rdata(pkt)) + return LDNS_RCODE_FORMERR; + return 0; + } + + if( (msg->qtype == LDNS_RR_TYPE_RRSIG || + msg->qtype == LDNS_RR_TYPE_ANY) + && sig_is_double(pkt, rrset, ldns_buffer_current(pkt))) { + if(!skip_ttl_rdata(pkt)) + return LDNS_RCODE_FORMERR; + return 0; + } + + /* create rr */ + if(!(rr = (struct rr_parse*)regional_alloc(region, sizeof(*rr)))) + return LDNS_RCODE_SERVFAIL; + rr->outside_packet = 0; + rr->ttl_data = ldns_buffer_current(pkt); + rr->next = 0; + if(type == LDNS_RR_TYPE_RRSIG && rrset->type != LDNS_RR_TYPE_RRSIG) { + if(rrset->rrsig_last) + rrset->rrsig_last->next = rr; + else rrset->rrsig_first = rr; + rrset->rrsig_last = rr; + rrset->rrsig_count++; + } else { + if(rrset->rr_last) + rrset->rr_last->next = rr; + else rrset->rr_first = rr; + rrset->rr_last = rr; + rrset->rr_count++; + } + + /* calc decompressed size */ + if(!calc_size(pkt, type, rr)) + return LDNS_RCODE_FORMERR; + rrset->size += rr->size; + + return 0; +} + +/** + * Parse packet RR section, for answer, authority and additional sections. + * @param pkt: packet, position at call must be at start of section. + * at end position is after section. + * @param msg: store results here. + * @param region: how to alloc results. + * @param section: section enum. + * @param num_rrs: how many rrs are in the section. + * @param num_rrsets: returns number of rrsets in the section. + * @return: 0 if OK, or rcode on error. + */ +static int +parse_section(ldns_buffer* pkt, struct msg_parse* msg, + struct regional* region, ldns_pkt_section section, + uint16_t num_rrs, size_t* num_rrsets) +{ + uint16_t i; + uint8_t* dname, *prev_dname_f = NULL, *prev_dname_l = NULL; + size_t dnamelen, prev_dnamelen = 0; + uint16_t type, prev_type = 0; + uint16_t dclass, prev_dclass = 0; + uint32_t rrset_flags = 0; + hashvalue_t hash = 0; + struct rrset_parse* rrset = NULL; + int r; + + if(num_rrs == 0) + return 0; + if(ldns_buffer_remaining(pkt) <= 0) + return LDNS_RCODE_FORMERR; + for(i=0; i<num_rrs; i++) { + /* parse this RR. */ + dname = ldns_buffer_current(pkt); + if((dnamelen = pkt_dname_len(pkt)) == 0) + return LDNS_RCODE_FORMERR; + if(ldns_buffer_remaining(pkt) < 10) /* type, class, ttl, len */ + return LDNS_RCODE_FORMERR; + type = ldns_buffer_read_u16(pkt); + ldns_buffer_read(pkt, &dclass, sizeof(dclass)); + + if(0) { /* debug show what is being parsed. */ + if(type == LDNS_RR_TYPE_RRSIG) { + uint16_t t; + if(pkt_rrsig_covered(pkt, + ldns_buffer_current(pkt), &t)) + fprintf(stderr, "parse of %s(%d) [%s(%d)]", + ldns_rr_descript(type)? + ldns_rr_descript(type)->_name: "??", + (int)type, + ldns_rr_descript(t)? + ldns_rr_descript(t)->_name: "??", + (int)t); + } else + fprintf(stderr, "parse of %s(%d)", + ldns_rr_descript(type)? + ldns_rr_descript(type)->_name: "??", + (int)type); + fprintf(stderr, " %s(%d) ", + ldns_lookup_by_id(ldns_rr_classes, + (int)ntohs(dclass))?ldns_lookup_by_id( + ldns_rr_classes, (int)ntohs(dclass))->name: + "??", (int)ntohs(dclass)); + dname_print(stderr, pkt, dname); + fprintf(stderr, "\n"); + } + + /* see if it is part of an existing RR set */ + if(!find_rrset(msg, pkt, dname, dnamelen, type, dclass, &hash, + &rrset_flags, &prev_dname_f, &prev_dname_l, + &prev_dnamelen, &prev_type, &prev_dclass, &rrset, + section, region)) + return LDNS_RCODE_SERVFAIL; + if(!rrset) { + /* it is a new RR set. hash&flags already calculated.*/ + (*num_rrsets)++; + rrset = new_rrset(msg, dname, dnamelen, type, dclass, + hash, rrset_flags, section, region); + if(!rrset) + return LDNS_RCODE_SERVFAIL; + } + else if(0) { + fprintf(stderr, "is part of existing: "); + dname_print(stderr, pkt, rrset->dname); + fprintf(stderr, " type %s(%d)\n", + ldns_rr_descript(rrset->type)? + ldns_rr_descript(rrset->type)->_name: "??", + (int)rrset->type); + } + /* add to rrset. */ + if((r=add_rr_to_rrset(rrset, pkt, msg, region, section, + type)) != 0) + return r; + } + return 0; +} + +int +parse_packet(ldns_buffer* pkt, struct msg_parse* msg, struct regional* region) +{ + int ret; + if(ldns_buffer_remaining(pkt) < LDNS_HEADER_SIZE) + return LDNS_RCODE_FORMERR; + /* read the header */ + ldns_buffer_read(pkt, &msg->id, sizeof(uint16_t)); + msg->flags = ldns_buffer_read_u16(pkt); + msg->qdcount = ldns_buffer_read_u16(pkt); + msg->ancount = ldns_buffer_read_u16(pkt); + msg->nscount = ldns_buffer_read_u16(pkt); + msg->arcount = ldns_buffer_read_u16(pkt); + if(msg->qdcount > 1) + return LDNS_RCODE_FORMERR; + if((ret = parse_query_section(pkt, msg)) != 0) + return ret; + if((ret = parse_section(pkt, msg, region, LDNS_SECTION_ANSWER, + msg->ancount, &msg->an_rrsets)) != 0) + return ret; + if((ret = parse_section(pkt, msg, region, LDNS_SECTION_AUTHORITY, + msg->nscount, &msg->ns_rrsets)) != 0) + return ret; + if(ldns_buffer_remaining(pkt) == 0 && msg->arcount == 1) { + /* BIND accepts leniently that an EDNS record is missing. + * so, we do too. */ + } else if((ret = parse_section(pkt, msg, region, + LDNS_SECTION_ADDITIONAL, msg->arcount, &msg->ar_rrsets)) != 0) + return ret; + /* if(ldns_buffer_remaining(pkt) > 0) { */ + /* there is spurious data at end of packet. ignore */ + /* } */ + msg->rrset_count = msg->an_rrsets + msg->ns_rrsets + msg->ar_rrsets; + return 0; +} + +int +parse_extract_edns(struct msg_parse* msg, struct edns_data* edns) +{ + struct rrset_parse* rrset = msg->rrset_first; + struct rrset_parse* prev = 0; + struct rrset_parse* found = 0; + struct rrset_parse* found_prev = 0; + /* since the class encodes the UDP size, we cannot use hash table to + * find the EDNS OPT record. Scan the packet. */ + while(rrset) { + if(rrset->type == LDNS_RR_TYPE_OPT) { + /* only one OPT RR allowed. */ + if(found) return LDNS_RCODE_FORMERR; + /* found it! */ + found_prev = prev; + found = rrset; + } + prev = rrset; + rrset = rrset->rrset_all_next; + } + if(!found) { + memset(edns, 0, sizeof(*edns)); + edns->udp_size = 512; + return 0; + } + /* check the found RRset */ + /* most lenient check possible. ignore dname, use last opt */ + if(found->section != LDNS_SECTION_ADDITIONAL) + return LDNS_RCODE_FORMERR; + if(found->rr_count == 0) + return LDNS_RCODE_FORMERR; + if(0) { /* strict checking of dname and RRcount */ + if(found->dname_len != 1 || !found->dname + || found->dname[0] != 0) return LDNS_RCODE_FORMERR; + if(found->rr_count != 1) return LDNS_RCODE_FORMERR; + } + log_assert(found->rr_first && found->rr_last); + + /* remove from packet */ + if(found_prev) found_prev->rrset_all_next = found->rrset_all_next; + else msg->rrset_first = found->rrset_all_next; + if(found == msg->rrset_last) + msg->rrset_last = found_prev; + msg->arcount --; + msg->ar_rrsets --; + msg->rrset_count --; + + /* take the data ! */ + edns->edns_present = 1; + edns->ext_rcode = found->rr_last->ttl_data[0]; + edns->edns_version = found->rr_last->ttl_data[1]; + edns->bits = ldns_read_uint16(&found->rr_last->ttl_data[2]); + edns->udp_size = ntohs(found->rrset_class); + /* ignore rdata and rrsigs */ + return 0; +} + +int +parse_edns_from_pkt(ldns_buffer* pkt, struct edns_data* edns) +{ + log_assert(LDNS_QDCOUNT(ldns_buffer_begin(pkt)) == 1); + log_assert(LDNS_ANCOUNT(ldns_buffer_begin(pkt)) == 0); + log_assert(LDNS_NSCOUNT(ldns_buffer_begin(pkt)) == 0); + /* check edns section is present */ + if(LDNS_ARCOUNT(ldns_buffer_begin(pkt)) > 1) { + return LDNS_RCODE_FORMERR; + } + if(LDNS_ARCOUNT(ldns_buffer_begin(pkt)) == 0) { + memset(edns, 0, sizeof(*edns)); + edns->udp_size = 512; + return 0; + } + /* domain name must be the root of length 1. */ + if(pkt_dname_len(pkt) != 1) + return LDNS_RCODE_FORMERR; + if(ldns_buffer_remaining(pkt) < 10) /* type, class, ttl, rdatalen */ + return LDNS_RCODE_FORMERR; + if(ldns_buffer_read_u16(pkt) != LDNS_RR_TYPE_OPT) + return LDNS_RCODE_FORMERR; + edns->edns_present = 1; + edns->udp_size = ldns_buffer_read_u16(pkt); /* class is udp size */ + edns->ext_rcode = ldns_buffer_read_u8(pkt); /* ttl used for bits */ + edns->edns_version = ldns_buffer_read_u8(pkt); + edns->bits = ldns_buffer_read_u16(pkt); + /* ignore rdata and rrsigs */ + return 0; +} |