monero/external/unbound/util/data/msgparse.h
Erik de Castro Lopo a85b5759f3 Upgrade unbound library
These files were pulled from the 1.6.3 release tarball.

This new version builds against OpenSSL version 1.1 which will be
the default in the new Debian Stable which is due to be released
RealSoonNow (tm).
2017-06-17 23:04:00 +10:00

334 lines
12 KiB
C

/*
* 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 "sldns/pkthdr.h"
#include "sldns/rrdef.h"
struct sldns_buffer;
struct rrset_parse;
struct rr_parse;
struct regional;
struct edns_option;
/** 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;
/** Maximum Negative TTL that is allowed */
extern time_t MAX_NEG_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_type 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
* rdata is parsed in a list (has accessor functions). allocated in a
* region.
*/
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;
/** rdata element list, or NULL if none */
struct edns_option* opt_list;
};
/**
* EDNS option
*/
struct edns_option {
/** next item in list */
struct edns_option* next;
/** type of this edns option */
uint16_t opt_code;
/** length of this edns option (cannot exceed uint16 in encoding) */
size_t opt_len;
/** data of this edns option; allocated in region, or NULL if len=0 */
uint8_t* opt_data;
};
/**
* 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.
* @param region: region to alloc results in (edns option contents)
* @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,
struct regional* region);
/**
* 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.
* @param region: region to alloc results in (edns option contents)
* @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,
struct regional* region);
/**
* 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_type 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_type 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);
/**
* Log the edns options in the edns option list.
* @param level: the verbosity level.
* @param info_str: the informational string to be printed before the options.
* @param list: the edns option list.
*/
void log_edns_opt_list(enum verbosity_value level, const char* info_str,
struct edns_option* list);
#endif /* UTIL_DATA_MSGPARSE_H */