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-rw-r--r--external/unbound/util/data/msgparse.c1022
1 files changed, 1022 insertions, 0 deletions
diff --git a/external/unbound/util/data/msgparse.c b/external/unbound/util/data/msgparse.c
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+++ b/external/unbound/util/data/msgparse.c
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+/*
+ * 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 COPYRIGHT
+ * HOLDER 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 "util/data/msgparse.h"
+#include "util/data/dname.h"
+#include "util/data/packed_rrset.h"
+#include "util/storage/lookup3.h"
+#include "util/regional.h"
+#include "ldns/rrdef.h"
+#include "ldns/sbuffer.h"
+#include "ldns/parseutil.h"
+#include "ldns/wire2str.h"
+
+/** smart comparison of (compressed, valid) dnames from packet */
+static int
+smart_compare(sldns_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 = sldns_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, sldns_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(sldns_buffer* pkt)
+{
+ /* we are at ttl position in packet. */
+ size_t pos = sldns_buffer_position(pkt);
+ uint16_t rdatalen;
+ if(sldns_buffer_remaining(pkt) < 7) /* ttl+len+root */
+ return 0; /* eek! */
+ sldns_buffer_skip(pkt, 4); /* ttl */;
+ rdatalen = sldns_buffer_read_u16(pkt);
+ if(sldns_buffer_remaining(pkt) < rdatalen) {
+ sldns_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) {
+ sldns_buffer_set_position(pkt, pos);
+ return 0; /* parse error */
+ }
+
+ /* see if SOA bit is set. */
+ if(sldns_buffer_position(pkt) < pos+4+rdatalen) {
+ /* nsec type bitmap contains items */
+ uint8_t win, blen, bits;
+ /* need: windownum, bitmap len, firstbyte */
+ if(sldns_buffer_position(pkt)+3 > pos+4+rdatalen) {
+ sldns_buffer_set_position(pkt, pos);
+ return 0; /* malformed nsec */
+ }
+ win = sldns_buffer_read_u8(pkt);
+ blen = sldns_buffer_read_u8(pkt);
+ bits = sldns_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)) {
+ sldns_buffer_set_position(pkt, pos);
+ return 1;
+ }
+ }
+
+ sldns_buffer_set_position(pkt, pos);
+ return 0;
+}
+
+/** Calculate rrset flags */
+static uint32_t
+pkt_rrset_flags(sldns_buffer* pkt, uint16_t type, sldns_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(sldns_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(sldns_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, sldns_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, sldns_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(sldns_buffer* pkt, uint8_t* here, uint16_t* type)
+{
+ size_t pos = sldns_buffer_position(pkt);
+ sldns_buffer_set_position(pkt, (size_t)(here-sldns_buffer_begin(pkt)));
+ /* ttl + len + size of small rrsig(rootlabel, no signature) */
+ if(sldns_buffer_remaining(pkt) < 4+2+19)
+ return 0;
+ sldns_buffer_skip(pkt, 4); /* ttl */
+ if(sldns_buffer_read_u16(pkt) < 19) /* too short */ {
+ sldns_buffer_set_position(pkt, pos);
+ return 0;
+ }
+ *type = sldns_buffer_read_u16(pkt);
+ sldns_buffer_set_position(pkt, pos);
+ return 1;
+}
+
+/** true if covered type equals prevtype */
+static int
+pkt_rrsig_covered_equals(sldns_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,
+ sldns_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(sldns_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(sldns_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,
+ sldns_buffer* pkt, uint16_t datatype, uint32_t rrset_flags,
+ int hasother, sldns_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, sldns_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,
+ sldns_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, sldns_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,
+ sldns_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(sldns_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(sldns_buffer_remaining(pkt) <= 0)
+ return LDNS_RCODE_FORMERR;
+ msg->qname = sldns_buffer_current(pkt);
+ if((msg->qname_len = pkt_dname_len(pkt)) == 0)
+ return LDNS_RCODE_FORMERR;
+ if(sldns_buffer_remaining(pkt) < sizeof(uint16_t)*2)
+ return LDNS_RCODE_FORMERR;
+ msg->qtype = sldns_buffer_read_u16(pkt);
+ msg->qclass = sldns_buffer_read_u16(pkt);
+ return 0;
+}
+
+size_t
+get_rdf_size(sldns_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(0); /* 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(sldns_buffer* pkt, uint16_t type, struct rr_parse* rr)
+{
+ const sldns_rr_descriptor* desc;
+ uint16_t pkt_len; /* length of rr inside the packet */
+ rr->size = sizeof(uint16_t); /* the rdatalen */
+ sldns_buffer_skip(pkt, 4); /* skip ttl */
+ pkt_len = sldns_buffer_read_u16(pkt);
+ if(sldns_buffer_remaining(pkt) < pkt_len)
+ return 0;
+ desc = sldns_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 = sldns_buffer_position(pkt);
+ if((len = pkt_dname_len(pkt)) == 0)
+ return 0; /* malformed dname */
+ if(sldns_buffer_position(pkt)-oldpos > pkt_len)
+ return 0; /* dname exceeds rdata */
+ pkt_len -= sldns_buffer_position(pkt)-oldpos;
+ rr->size += len;
+ count--;
+ len = 0;
+ break;
+ case LDNS_RDF_TYPE_STR:
+ if(pkt_len < 1) {
+ /* NOTREACHED, due to 'while(>0)' */
+ return 0; /* len byte exceeds rdata */
+ }
+ len = sldns_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;
+ sldns_buffer_skip(pkt, (ssize_t)len);
+ rr->size += len;
+ }
+ rdf++;
+ }
+ }
+ /* remaining rdata */
+ rr->size += pkt_len;
+ sldns_buffer_skip(pkt, (ssize_t)pkt_len);
+ return 1;
+}
+
+/** skip rr ttl and rdata */
+static int
+skip_ttl_rdata(sldns_buffer* pkt)
+{
+ uint16_t rdatalen;
+ if(sldns_buffer_remaining(pkt) < 6) /* ttl + rdatalen */
+ return 0;
+ sldns_buffer_skip(pkt, 4); /* ttl */
+ rdatalen = sldns_buffer_read_u16(pkt);
+ if(sldns_buffer_remaining(pkt) < rdatalen)
+ return 0;
+ sldns_buffer_skip(pkt, (ssize_t)rdatalen);
+ return 1;
+}
+
+/** see if RRSIG is a duplicate of another */
+static int
+sig_is_double(sldns_buffer* pkt, struct rrset_parse* rrset, uint8_t* ttldata)
+{
+ uint16_t rlen, siglen;
+ size_t pos = sldns_buffer_position(pkt);
+ struct rr_parse* sig;
+ if(sldns_buffer_remaining(pkt) < 6)
+ return 0;
+ sldns_buffer_skip(pkt, 4); /* ttl */
+ rlen = sldns_buffer_read_u16(pkt);
+ if(sldns_buffer_remaining(pkt) < rlen) {
+ sldns_buffer_set_position(pkt, pos);
+ return 0;
+ }
+ sldns_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, sldns_buffer* pkt,
+ struct msg_parse* msg, struct regional* region,
+ sldns_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, sldns_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 = sldns_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(sldns_buffer* pkt, struct msg_parse* msg,
+ struct regional* region, sldns_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(sldns_buffer_remaining(pkt) <= 0)
+ return LDNS_RCODE_FORMERR;
+ for(i=0; i<num_rrs; i++) {
+ /* parse this RR. */
+ dname = sldns_buffer_current(pkt);
+ if((dnamelen = pkt_dname_len(pkt)) == 0)
+ return LDNS_RCODE_FORMERR;
+ if(sldns_buffer_remaining(pkt) < 10) /* type, class, ttl, len */
+ return LDNS_RCODE_FORMERR;
+ type = sldns_buffer_read_u16(pkt);
+ sldns_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,
+ sldns_buffer_current(pkt), &t))
+ fprintf(stderr, "parse of %s(%d) [%s(%d)]",
+ sldns_rr_descript(type)?
+ sldns_rr_descript(type)->_name: "??",
+ (int)type,
+ sldns_rr_descript(t)?
+ sldns_rr_descript(t)->_name: "??",
+ (int)t);
+ } else
+ fprintf(stderr, "parse of %s(%d)",
+ sldns_rr_descript(type)?
+ sldns_rr_descript(type)->_name: "??",
+ (int)type);
+ fprintf(stderr, " %s(%d) ",
+ sldns_lookup_by_id(sldns_rr_classes,
+ (int)ntohs(dclass))?sldns_lookup_by_id(
+ sldns_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",
+ sldns_rr_descript(rrset->type)?
+ sldns_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(sldns_buffer* pkt, struct msg_parse* msg, struct regional* region)
+{
+ int ret;
+ if(sldns_buffer_remaining(pkt) < LDNS_HEADER_SIZE)
+ return LDNS_RCODE_FORMERR;
+ /* read the header */
+ sldns_buffer_read(pkt, &msg->id, sizeof(uint16_t));
+ msg->flags = sldns_buffer_read_u16(pkt);
+ msg->qdcount = sldns_buffer_read_u16(pkt);
+ msg->ancount = sldns_buffer_read_u16(pkt);
+ msg->nscount = sldns_buffer_read_u16(pkt);
+ msg->arcount = sldns_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(sldns_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(sldns_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 = sldns_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(sldns_buffer* pkt, struct edns_data* edns)
+{
+ log_assert(LDNS_QDCOUNT(sldns_buffer_begin(pkt)) == 1);
+ log_assert(LDNS_ANCOUNT(sldns_buffer_begin(pkt)) == 0);
+ log_assert(LDNS_NSCOUNT(sldns_buffer_begin(pkt)) == 0);
+ /* check edns section is present */
+ if(LDNS_ARCOUNT(sldns_buffer_begin(pkt)) > 1) {
+ return LDNS_RCODE_FORMERR;
+ }
+ if(LDNS_ARCOUNT(sldns_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(sldns_buffer_remaining(pkt) < 10) /* type, class, ttl, rdatalen */
+ return LDNS_RCODE_FORMERR;
+ if(sldns_buffer_read_u16(pkt) != LDNS_RR_TYPE_OPT)
+ return LDNS_RCODE_FORMERR;
+ edns->edns_present = 1;
+ edns->udp_size = sldns_buffer_read_u16(pkt); /* class is udp size */
+ edns->ext_rcode = sldns_buffer_read_u8(pkt); /* ttl used for bits */
+ edns->edns_version = sldns_buffer_read_u8(pkt);
+ edns->bits = sldns_buffer_read_u16(pkt);
+ /* ignore rdata and rrsigs */
+ return 0;
+}