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Diffstat (limited to 'external/unbound/util/data/msgparse.h')
| -rw-r--r-- | external/unbound/util/data/msgparse.h | 301 |
1 files changed, 301 insertions, 0 deletions
diff --git a/external/unbound/util/data/msgparse.h b/external/unbound/util/data/msgparse.h new file mode 100644 index 000000000..221a45aad --- /dev/null +++ b/external/unbound/util/data/msgparse.h @@ -0,0 +1,301 @@ +/* + * 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 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 + * Contains message parsing data structures. + * These point back into the packet buffer. + * + * During parsing RRSIGS are put together with the rrsets they (claim to) sign. + * This process works as follows: + * o if RRSIG follows the data rrset, it is added to the rrset rrsig list. + * o if no matching data rrset is found, the RRSIG becomes a new rrset. + * o If the data rrset later follows the RRSIG + * o See if the RRSIG rrset contains multiple types, and needs to + * have the rrsig(s) for that data type split off. + * o Put the data rr as data type in the rrset and rrsig in list. + * o RRSIGs are allowed to move to a different section. The section of + * the data item is used for the final rrset. + * o multiple signatures over an RRset are possible. + * + * For queries of qtype=RRSIG, some special handling is needed, to avoid + * splitting the RRSIG in the answer section. + * o duplicate, not split, RRSIGs from the answer section, if qtype=RRSIG. + * o check for doubles in the rrsig list when adding an RRSIG to data, + * so that a data rrset is signed by RRSIGs with different rdata. + * when qtype=RRSIG. + * This will move the RRSIG from the answer section to sign the data further + * in the packet (if possible). If then after that, more RRSIGs are found + * that sign the data as well, doubles are removed. + */ + +#ifndef UTIL_DATA_MSGPARSE_H +#define UTIL_DATA_MSGPARSE_H +#include "util/storage/lruhash.h" +#include "ldns/pkthdr.h" +#include "ldns/rrdef.h" +struct sldns_buffer; +struct rrset_parse; +struct rr_parse; +struct regional; + +/** number of buckets in parse rrset hash table. Must be power of 2. */ +#define PARSE_TABLE_SIZE 32 +/** Maximum TTL that is allowed. */ +extern time_t MAX_TTL; +/** Minimum TTL that is allowed. */ +extern time_t MIN_TTL; +/** Negative cache time (for entries without any RRs.) */ +#define NORR_TTL 5 /* seconds */ + +/** + * 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, host order. 0 if qdcount=0 */ + uint16_t qtype; + /** query class, host 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 + */ + sldns_pkt_section section; + /** start of (possibly compressed) dname in packet */ + uint8_t* dname; + /** length of the dname uncompressed wireformat */ + size_t dname_len; + /** type, host order. */ + uint16_t type; + /** class, network order. var 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; + /** sum of RR rdata sizes */ + size_t size; + /** 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; + /** number of RRSIGs over this rrset. */ + size_t rrsig_count; + /** linked list of RRsig RRs over this rrset. */ + struct rr_parse* rrsig_first; + /** last in list of RRSIG RRs over this rrset. */ + struct rr_parse* rrsig_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; + /** true if ttl_data is not part of the packet, but elsewhere in mem. + * Set for generated CNAMEs for DNAMEs. */ + int outside_packet; + /** the length of the rdata if allocated (with no dname compression)*/ + size_t size; + /** next in list of RRs. */ + struct rr_parse* next; +}; + +/** Check if label length is first octet of a compression pointer, pass u8. */ +#define LABEL_IS_PTR(x) ( ((x)&0xc0) == 0xc0 ) +/** Calculate destination offset of a compression pointer. pass first and + * second octets of the compression pointer. */ +#define PTR_OFFSET(x, y) ( ((x)&0x3f)<<8 | (y) ) +/** create a compression pointer to the given offset. */ +#define PTR_CREATE(offset) ((uint16_t)(0xc000 | (offset))) + +/** error codes, extended with EDNS, so > 15. */ +#define EDNS_RCODE_BADVERS 16 /** bad EDNS version */ +/** largest valid compression offset */ +#define PTR_MAX_OFFSET 0x3fff + +/** + * EDNS data storage + * EDNS rdata is ignored. + */ +struct edns_data { + /** if EDNS OPT record was present */ + int edns_present; + /** Extended RCODE */ + uint8_t ext_rcode; + /** The EDNS version number */ + uint8_t edns_version; + /** the EDNS bits field from ttl (host order): Z */ + uint16_t bits; + /** UDP reassembly size. */ + uint16_t udp_size; +}; + +/** + * Obtain size in the packet of an rr type, that is before dname type. + * Do TYPE_DNAME, and type STR, yourself. Gives size for most regular types. + * @param rdf: the rdf type from the descriptor. + * @return: size in octets. 0 on failure. + */ +size_t get_rdf_size(sldns_rdf_type rdf); + +/** + * 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(struct sldns_buffer* pkt, struct msg_parse* msg, + struct regional* region); + +/** + * After parsing the packet, extract EDNS data from packet. + * If not present this is noted in the data structure. + * If a parse error happens, an error code is returned. + * + * Quirks: + * o ignores OPT rdata. + * o ignores OPT owner name. + * o ignores extra OPT records, except the last one in the packet. + * + * @param msg: parsed message structure. Modified on exit, if EDNS was present + * it is removed from the additional section. + * @param edns: the edns data is stored here. Does not have to be initialised. + * @return: 0 on success. or an RCODE on an error. + * RCODE formerr if OPT in wrong section, and so on. + */ +int parse_extract_edns(struct msg_parse* msg, struct edns_data* edns); + +/** + * If EDNS data follows a query section, extract it and initialize edns struct. + * @param pkt: the packet. position at start must be right after the query + * section. At end, right after EDNS data or no movement if failed. + * @param edns: the edns data allocated by the caller. Does not have to be + * initialised. + * @return: 0 on success, or an RCODE on error. + * RCODE formerr if OPT is badly formatted and so on. + */ +int parse_edns_from_pkt(struct sldns_buffer* pkt, struct edns_data* edns); + +/** + * Calculate hash value for rrset in packet. + * @param pkt: the packet. + * @param dname: pointer to uncompressed dname, or compressed dname in packet. + * @param type: rrset type in host order. + * @param dclass: rrset class in network order. + * @param rrset_flags: rrset flags (same as packed_rrset flags). + * @return hash value + */ +hashvalue_t pkt_hash_rrset(struct sldns_buffer* pkt, uint8_t* dname, uint16_t type, + uint16_t dclass, uint32_t rrset_flags); + +/** + * Lookup in msg hashtable to find a rrset. + * @param msg: with the hashtable. + * @param pkt: packet for compressed names. + * @param h: hash value + * @param rrset_flags: flags of rrset sought for. + * @param dname: name of rrset sought for. + * @param dnamelen: len of dname. + * @param type: rrset type, host order. + * @param dclass: rrset class, network order. + * @return NULL or the rrset_parse if found. + */ +struct rrset_parse* msgparse_hashtable_lookup(struct msg_parse* msg, + struct sldns_buffer* pkt, hashvalue_t h, uint32_t rrset_flags, + uint8_t* dname, size_t dnamelen, uint16_t type, uint16_t dclass); + +/** + * Remove rrset from hash table. + * @param msg: with hashtable. + * @param rrset: with hash value and id info. + */ +void msgparse_bucket_remove(struct msg_parse* msg, struct rrset_parse* rrset); + +#endif /* UTIL_DATA_MSGPARSE_H */ |