- copy and decompress dnames.
- store calculated hash value too.
- routine to create message out of stored information.
+ - util/data/msgparse.c for message parsing code.
16 April 2007: Wouter
- following a small change in LDNS, parsing code calculates the
--- /dev/null
+/*
+ * 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.
+ */
+#include "config.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/region-allocator.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( (*dnow & 0xc0) == 0xc0) {
+ /* ptr points to a previous dname */
+ uint8_t* p = ldns_buffer_at(pkt, (dnow[0]&0x3f)<<8 | dnow[1]);
+ if( p == dprfirst || p == dprlast )
+ return 0;
+ /* prev dname is also a ptr, both ptrs are the same. */
+ /* if( (*dprfirst & 0xc0) == 0xc0 &&
+ dprfirst[0] == dnow[0] && dprfirst[1] == dnow[1])
+ return 0; */
+ if( (*dprlast & 0xc0) == 0xc0 &&
+ dprlast[0] == dnow[0] && dprlast[1] == dnow[1])
+ return 0;
+ /* checks for prev dnames pointing forwards in the packet
+ } else {
+ if( (*dprfirst & 0xc0) == 0xc0 ) {
+ if(ldns_buffer_at(pkt, (dprfirst[0]&0x3f)<<8 |
+ dprfirst[1]) == dnow)
+ return 0;
+ }
+ if( (*dprlast & 0xc0) == 0xc0 ) {
+ if(ldns_buffer_at(pkt, (dprlast[0]&0x3f)<<8 |
+ dprlast[1]) == dnow)
+ return 0;
+ }
+ */
+ }
+ return dname_pkt_compare(pkt, dnow, dprlast);
+}
+
+/** 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+rdatalen) {
+ /* nsec type bitmap contains items */
+ uint8_t win, blen, bits;
+ /* need: windownum, bitmap len, firstbyte */
+ if(ldns_buffer_position(pkt)+3 <= pos+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 hash value for rrset in packet. */
+static hashvalue_t
+pkt_hash_rrset(struct msg_parse* msg, ldns_buffer* pkt, uint8_t* dname,
+ uint16_t type, uint16_t dclass, uint32_t* rrset_flags)
+{
+ hashvalue_t h = 0xab;
+ if(msg->flags & BIT_CD)
+ *rrset_flags = PACKED_RRSET_CD;
+ else *rrset_flags = 0;
+ if(type == htons(LDNS_RR_TYPE_NSEC) && nsec_at_apex(pkt))
+ *rrset_flags |= PACKED_RRSET_NSEC_AT_APEX;
+
+ h = hashlittle(&type, sizeof(type), h);
+ h = hashlittle(&dclass, sizeof(dclass), h);
+ h = hashlittle(rrset_flags, sizeof(uint32_t), h);
+ h = dname_pkt_hash(pkt, dname, 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;
+}
+
+
+/**
+ * Lookup in msg hashtable to find a rrset
+ */
+static struct rrset_parse*
+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;
+}
+
+/** 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.
+ * @return the rrset if found, or null if no matching rrset exists.
+ */
+static struct rrset_parse*
+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)
+{
+ 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) {
+ /* same as previous */
+ *prev_dname_last = dname;
+ return *rrset_prev;
+ }
+
+ }
+ /* find by hashing and lookup in hashtable */
+ *hash = pkt_hash_rrset(msg, pkt, dname, type, dclass, rrset_flags);
+ *rrset_prev = 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 *rrset_prev;
+}
+
+/**
+ * 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 = query_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;
+}
+
+/**
+ * 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, region_type* region)
+{
+ struct rrset_parse* p = region_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->rr_first = 0;
+ p->rr_last = 0;
+ return p;
+}
+
+/** Add rr (from packet here) to rrset, skips rr */
+static int
+add_rr_to_rrset(struct rrset_parse* rrset, ldns_buffer* pkt,
+ region_type* region, ldns_pkt_section section)
+{
+ uint16_t rdatalen;
+ /* check section of rrset. */
+ if(rrset->section != section) {
+ /* silently drop it */
+ verbose(VERB_DETAIL, "Packet contains rrset data in "
+ "multiple sections, dropped last part.");
+ } else {
+ /* create rr */
+ struct rr_parse* rr = region_alloc(region, sizeof(*rr));
+ if(!rr) return LDNS_RCODE_SERVFAIL;
+ rr->ttl_data = ldns_buffer_current(pkt);
+ rr->next = 0;
+ if(rrset->rr_last)
+ rrset->rr_last->next = rr;
+ else rrset->rr_first = rr;
+ rrset->rr_last = rr;
+ rrset->rr_count++;
+ }
+
+ /* forwards */
+ if(ldns_buffer_remaining(pkt) < 6) /* ttl + rdatalen */
+ return LDNS_RCODE_FORMERR;
+ ldns_buffer_skip(pkt, 4); /* ttl */
+ rdatalen = ldns_buffer_read_u16(pkt);
+ if(ldns_buffer_remaining(pkt) < rdatalen)
+ return LDNS_RCODE_FORMERR;
+ ldns_buffer_skip(pkt, (ssize_t)rdatalen);
+ 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, region_type* 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, *rrset_prev = 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;
+ ldns_buffer_read(pkt, &type, sizeof(type));
+ ldns_buffer_read(pkt, &dclass, sizeof(dclass));
+
+ /* see if it is part of an existing RR set */
+ if((rrset = find_rrset(msg, pkt, dname, dnamelen, type, dclass,
+ &hash, &rrset_flags, &prev_dname_f, &prev_dname_l,
+ &prev_dnamelen, &prev_type, &prev_dclass,
+ &rrset_prev)) != 0) {
+ /* check if it fits the existing rrset */
+ /* add to rrset. */
+ } else {
+ /* 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;
+ rrset_prev = rrset;
+ }
+ if((r=add_rr_to_rrset(rrset, pkt, region, section)))
+ return r;
+ }
+ return 0;
+}
+
+int
+parse_packet(ldns_buffer* pkt, struct msg_parse* msg, region_type* 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((ret = parse_section(pkt, msg, region, LDNS_SECTION_ADDITIONAL,
+ msg->arcount, &msg->ar_rrsets)) != 0)
+ return ret;
+ if(ldns_buffer_remaining(pkt) > 0) {
+ /* spurious data at end of packet. ignore */
+ verbose(VERB_DETAIL, "spurious data at end of packet ignored");
+ }
+ return 0;
+}
--- /dev/null
+/*
+ * util/data/msgparse.h - 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.
+ */
+
+#ifndef UTIL_DATA_MSGPARSE_H
+#define UTIL_DATA_MSGPARSE_H
+#include "util/storage/lruhash.h"
+struct rrset_parse;
+struct rr_parse;
+struct region;
+
+/** number of buckets in parse rrset hash table. Must be power of 2. */
+#define PARSE_TABLE_SIZE 1024
+/** Maximum TTL that is allowed. */
+#define MAX_TTL 3600*24*365*10 /* ten years */
+
+/**
+ * Data stored in scratch pad memory during parsing.
+ * Stores the data that will enter into the msgreply and packet result.
+ */
+struct msg_parse {
+ /** id from message, network format. */
+ uint16_t id;
+ /** flags from message, host format. */
+ uint16_t flags;
+ /** count of RRs, host format */
+ uint16_t qdcount;
+ /** count of RRs, host format */
+ uint16_t ancount;
+ /** count of RRs, host format */
+ uint16_t nscount;
+ /** count of RRs, host format */
+ uint16_t arcount;
+ /** count of RRsets per section. */
+ size_t an_rrsets;
+ /** count of RRsets per section. */
+ size_t ns_rrsets;
+ /** count of RRsets per section. */
+ size_t ar_rrsets;
+ /** total number of rrsets found. */
+ size_t rrset_count;
+
+ /** query dname (pointer to start location in packet, NULL if none */
+ uint8_t* qname;
+ /** length of query dname in octets, 0 if none */
+ size_t qname_len;
+ /** query type, network order. 0 if qdcount=0 */
+ uint16_t qtype;
+ /** query class, network order. 0 if qdcount=0 */
+ uint16_t qclass;
+
+ /**
+ * Hash table array used during parsing to lookup rrset types.
+ * Based on name, type, class. Same hash value as in rrset cache.
+ */
+ struct rrset_parse* hashtable[PARSE_TABLE_SIZE];
+
+ /** linked list of rrsets that have been found (in order). */
+ struct rrset_parse* rrset_first;
+ /** last element of rrset list. */
+ struct rrset_parse* rrset_last;
+};
+
+/**
+ * Data stored for an rrset during parsing.
+ */
+struct rrset_parse {
+ /** next in hash bucket */
+ struct rrset_parse* rrset_bucket_next;
+ /** next in list of all rrsets */
+ struct rrset_parse* rrset_all_next;
+ /** hash value of rrset */
+ hashvalue_t hash;
+ /** which section was it found in: one of
+ * LDNS_SECTION_ANSWER, LDNS_SECTION_AUTHORITY, LDNS_SECTION_ADDITIONAL
+ */
+ ldns_pkt_section section;
+ /** start of (possibly compressed) dname in packet */
+ uint8_t* dname;
+ /** length of the dname uncompressed wireformat */
+ size_t dname_len;
+ /** type, network order. */
+ uint16_t type;
+ /** class, network order. name so that it is not a c++ keyword. */
+ uint16_t rrset_class;
+ /** the flags for the rrset, like for packedrrset */
+ uint32_t flags;
+ /** number of RRs in the rr list */
+ size_t rr_count;
+ /** linked list of RRs in this rrset. */
+ struct rr_parse* rr_first;
+ /** last in list of RRs in this rrset. */
+ struct rr_parse* rr_last;
+};
+
+/**
+ * Data stored for an RR during parsing.
+ */
+struct rr_parse {
+ /**
+ * Pointer to the RR. Points to start of TTL value in the packet.
+ * Rdata length and rdata follow it.
+ * its dname, type and class are the same and stored for the rrset.
+ */
+ uint8_t* ttl_data;
+ /** the length of the rdata if allocated (with no dname compression)*/
+ size_t size;
+ /** next in list of RRs. */
+ struct rr_parse* next;
+};
+
+/**
+ * Parse the packet.
+ * @param pkt: packet, position at call must be at start of packet.
+ * at end position is after packet.
+ * @param msg: where to store results.
+ * @param region: how to alloc results.
+ * @return: 0 if OK, or rcode on error.
+ */
+int parse_packet(ldns_buffer* pkt, struct msg_parse* msg,
+ struct region* region);
+
+#endif /* UTIL_DATA_MSGPARSE_H */
#include "util/net_help.h"
#include "util/data/dname.h"
#include "util/region-allocator.h"
-
-struct rrset_parse;
-struct rr_parse;
-
-/** number of buckets in parse rrset hash table. Must be power of 2. */
-#define PARSE_TABLE_SIZE 1024
-/** Maximum TTL that is allowed. */
-#define MAX_TTL 3600*24*365*10 /* ten years */
-
-/**
- * Data stored in scratch pad memory during parsing.
- * Stores the data that will enter into the msgreply and packet result.
- */
-struct msg_parse {
- /** id from message, network format. */
- uint16_t id;
- /** flags from message, host format. */
- uint16_t flags;
- /** count of RRs, host format */
- uint16_t qdcount;
- /** count of RRs, host format */
- uint16_t ancount;
- /** count of RRs, host format */
- uint16_t nscount;
- /** count of RRs, host format */
- uint16_t arcount;
- /** count of RRsets per section. */
- size_t an_rrsets;
- /** count of RRsets per section. */
- size_t ns_rrsets;
- /** count of RRsets per section. */
- size_t ar_rrsets;
- /** total number of rrsets found. */
- size_t rrset_count;
-
- /** query dname (pointer to start location in packet, NULL if none */
- uint8_t* qname;
- /** length of query dname in octets, 0 if none */
- size_t qname_len;
- /** query type, network order. 0 if qdcount=0 */
- uint16_t qtype;
- /** query class, network order. 0 if qdcount=0 */
- uint16_t qclass;
-
- /**
- * Hash table array used during parsing to lookup rrset types.
- * Based on name, type, class. Same hash value as in rrset cache.
- */
- struct rrset_parse* hashtable[PARSE_TABLE_SIZE];
-
- /** linked list of rrsets that have been found (in order). */
- struct rrset_parse* rrset_first;
- /** last element of rrset list. */
- struct rrset_parse* rrset_last;
-};
-
-/**
- * Data stored for an rrset during parsing.
- */
-struct rrset_parse {
- /** next in hash bucket */
- struct rrset_parse* rrset_bucket_next;
- /** next in list of all rrsets */
- struct rrset_parse* rrset_all_next;
- /** hash value of rrset */
- hashvalue_t hash;
- /** which section was it found in: one of
- * LDNS_SECTION_ANSWER, LDNS_SECTION_AUTHORITY, LDNS_SECTION_ADDITIONAL
- */
- ldns_pkt_section section;
- /** start of (possibly compressed) dname in packet */
- uint8_t* dname;
- /** length of the dname uncompressed wireformat */
- size_t dname_len;
- /** type, network order. */
- uint16_t type;
- /** class, network order. name so that it is not a c++ keyword. */
- uint16_t rrset_class;
- /** the flags for the rrset, like for packedrrset */
- uint32_t flags;
- /** number of RRs in the rr list */
- size_t rr_count;
- /** linked list of RRs in this rrset. */
- struct rr_parse* rr_first;
- /** last in list of RRs in this rrset. */
- struct rr_parse* rr_last;
-};
-
-/**
- * Data stored for an RR during parsing.
- */
-struct rr_parse {
- /**
- * Pointer to the RR. Points to start of TTL value in the packet.
- * Rdata length and rdata follow it.
- * its dname, type and class are the same and stored for the rrset.
- */
- uint8_t* ttl_data;
- /** the length of the rdata if allocated (with no dname compression)*/
- size_t size;
- /** next in list of RRs. */
- struct rr_parse* next;
-};
-
-/** 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( (*dnow & 0xc0) == 0xc0) {
- /* ptr points to a previous dname */
- uint8_t* p = ldns_buffer_at(pkt, (dnow[0]&0x3f)<<8 | dnow[1]);
- if( p == dprfirst || p == dprlast )
- return 0;
- /* prev dname is also a ptr, both ptrs are the same. */
- /* if( (*dprfirst & 0xc0) == 0xc0 &&
- dprfirst[0] == dnow[0] && dprfirst[1] == dnow[1])
- return 0; */
- if( (*dprlast & 0xc0) == 0xc0 &&
- dprlast[0] == dnow[0] && dprlast[1] == dnow[1])
- return 0;
- /* checks for prev dnames pointing forwards in the packet
- } else {
- if( (*dprfirst & 0xc0) == 0xc0 ) {
- if(ldns_buffer_at(pkt, (dprfirst[0]&0x3f)<<8 |
- dprfirst[1]) == dnow)
- return 0;
- }
- if( (*dprlast & 0xc0) == 0xc0 ) {
- if(ldns_buffer_at(pkt, (dprlast[0]&0x3f)<<8 |
- dprlast[1]) == dnow)
- return 0;
- }
- */
- }
- return dname_pkt_compare(pkt, dnow, dprlast);
-}
-
-/** 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+rdatalen) {
- /* nsec type bitmap contains items */
- uint8_t win, blen, bits;
- /* need: windownum, bitmap len, firstbyte */
- if(ldns_buffer_position(pkt)+3 <= pos+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 hash value for rrset in packet. */
-static hashvalue_t
-pkt_hash_rrset(struct msg_parse* msg, ldns_buffer* pkt, uint8_t* dname,
- uint16_t type, uint16_t dclass, uint32_t* rrset_flags)
-{
- hashvalue_t h = 0xab;
- if(msg->flags & BIT_CD)
- *rrset_flags = PACKED_RRSET_CD;
- else *rrset_flags = 0;
- if(type == htons(LDNS_RR_TYPE_NSEC) && nsec_at_apex(pkt))
- *rrset_flags |= PACKED_RRSET_NSEC_AT_APEX;
-
- h = hashlittle(&type, sizeof(type), h);
- h = hashlittle(&dclass, sizeof(dclass), h);
- h = hashlittle(rrset_flags, sizeof(uint32_t), h);
- h = dname_pkt_hash(pkt, dname, 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;
-}
-
-
-/**
- * Lookup in msg hashtable to find a rrset
- */
-static struct rrset_parse*
-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;
-}
-
-/** 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.
- * @return the rrset if found, or null if no matching rrset exists.
- */
-static struct rrset_parse*
-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)
-{
- 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) {
- /* same as previous */
- *prev_dname_last = dname;
- return *rrset_prev;
- }
-
- }
- /* find by hashing and lookup in hashtable */
- *hash = pkt_hash_rrset(msg, pkt, dname, type, dclass, rrset_flags);
- *rrset_prev = 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 *rrset_prev;
-}
-
-/**
- * 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 = query_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;
-}
-
-/**
- * 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, region_type* region)
-{
- struct rrset_parse* p = region_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->rr_first = 0;
- p->rr_last = 0;
- return p;
-}
-
-/** Add rr (from packet here) to rrset, skips rr */
-static int
-add_rr_to_rrset(struct rrset_parse* rrset, ldns_buffer* pkt,
- region_type* region, ldns_pkt_section section)
-{
- uint16_t rdatalen;
- /* check section of rrset. */
- if(rrset->section != section) {
- /* silently drop it */
- verbose(VERB_DETAIL, "Packet contains rrset data in "
- "multiple sections, dropped last part.");
- } else {
- /* create rr */
- struct rr_parse* rr = region_alloc(region, sizeof(*rr));
- if(!rr) return LDNS_RCODE_SERVFAIL;
- rr->ttl_data = ldns_buffer_current(pkt);
- rr->next = 0;
- if(rrset->rr_last)
- rrset->rr_last->next = rr;
- else rrset->rr_first = rr;
- rrset->rr_last = rr;
- rrset->rr_count++;
- }
-
- /* forwards */
- if(ldns_buffer_remaining(pkt) < 6) /* ttl + rdatalen */
- return LDNS_RCODE_FORMERR;
- ldns_buffer_skip(pkt, 4); /* ttl */
- rdatalen = ldns_buffer_read_u16(pkt);
- if(ldns_buffer_remaining(pkt) < rdatalen)
- return LDNS_RCODE_FORMERR;
- ldns_buffer_skip(pkt, (ssize_t)rdatalen);
- 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, region_type* 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, *rrset_prev = 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;
- ldns_buffer_read(pkt, &type, sizeof(type));
- ldns_buffer_read(pkt, &dclass, sizeof(dclass));
-
- /* see if it is part of an existing RR set */
- if((rrset = find_rrset(msg, pkt, dname, dnamelen, type, dclass,
- &hash, &rrset_flags, &prev_dname_f, &prev_dname_l,
- &prev_dnamelen, &prev_type, &prev_dclass,
- &rrset_prev)) != 0) {
- /* check if it fits the existing rrset */
- /* add to rrset. */
- } else {
- /* 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;
- rrset_prev = rrset;
- }
- if((r=add_rr_to_rrset(rrset, pkt, region, section)))
- return r;
- }
- return 0;
-}
-
-/**
- * Parse the packet.
- * @param pkt: packet, position at call must be at start of packet.
- * at end position is after packet.
- * @param msg: where to store results.
- * @param region: how to alloc results.
- * @return: 0 if OK, or rcode on error.
- */
-static int
-parse_packet(ldns_buffer* pkt, struct msg_parse* msg,
- region_type* 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((ret = parse_section(pkt, msg, region, LDNS_SECTION_ADDITIONAL,
- msg->arcount, &msg->ar_rrsets)) != 0)
- return ret;
- if(ldns_buffer_remaining(pkt) > 0) {
- /* spurious data at end of packet. ignore */
- verbose(VERB_DETAIL, "spurious data at end of packet ignored");
- }
- return 0;
-}
+#include "util/data/msgparse.h"
/** copy and allocate an uncompressed dname. */
static uint8_t*
projects / thirdparty / unbound.git / commitdiff
