1238106Sdes/*
2238106Sdes * util/data/msgparse.h - parse wireformat DNS messages.
3238106Sdes *
4238106Sdes * Copyright (c) 2007, NLnet Labs. All rights reserved.
5238106Sdes *
6238106Sdes * This software is open source.
7238106Sdes *
8238106Sdes * Redistribution and use in source and binary forms, with or without
9238106Sdes * modification, are permitted provided that the following conditions
10238106Sdes * are met:
11238106Sdes *
12238106Sdes * Redistributions of source code must retain the above copyright notice,
13238106Sdes * this list of conditions and the following disclaimer.
14238106Sdes *
15238106Sdes * Redistributions in binary form must reproduce the above copyright notice,
16238106Sdes * this list of conditions and the following disclaimer in the documentation
17238106Sdes * and/or other materials provided with the distribution.
18238106Sdes *
19238106Sdes * Neither the name of the NLNET LABS nor the names of its contributors may
20238106Sdes * be used to endorse or promote products derived from this software without
21238106Sdes * specific prior written permission.
22238106Sdes *
23238106Sdes * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
24269257Sdes * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
25269257Sdes * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
26269257Sdes * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
27269257Sdes * HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
28269257Sdes * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
29269257Sdes * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
30269257Sdes * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
31269257Sdes * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
32269257Sdes * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
33269257Sdes * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
34238106Sdes */
35238106Sdes/**
36238106Sdes * \file
37238106Sdes * Contains message parsing data structures.
38238106Sdes * These point back into the packet buffer.
39238106Sdes *
40238106Sdes * During parsing RRSIGS are put together with the rrsets they (claim to) sign.
41238106Sdes * This process works as follows:
42238106Sdes *	o if RRSIG follows the data rrset, it is added to the rrset rrsig list.
43238106Sdes *	o if no matching data rrset is found, the RRSIG becomes a new rrset.
44238106Sdes *	o If the data rrset later follows the RRSIG
45238106Sdes *		o See if the RRSIG rrset contains multiple types, and needs to
46238106Sdes *		  have the rrsig(s) for that data type split off.
47238106Sdes *		o Put the data rr as data type in the rrset and rrsig in list.
48238106Sdes *	o RRSIGs are allowed to move to a different section. The section of
49238106Sdes *	  the data item is used for the final rrset.
50238106Sdes *	o multiple signatures over an RRset are possible.
51238106Sdes *
52238106Sdes * For queries of qtype=RRSIG, some special handling is needed, to avoid
53238106Sdes * splitting the RRSIG in the answer section.
54238106Sdes *	o duplicate, not split, RRSIGs from the answer section, if qtype=RRSIG.
55238106Sdes *	o check for doubles in the rrsig list when adding an RRSIG to data,
56238106Sdes *	  so that a data rrset is signed by RRSIGs with different rdata.
57238106Sdes *	  when qtype=RRSIG.
58238106Sdes * This will move the RRSIG from the answer section to sign the data further
59238106Sdes * in the packet (if possible). If then after that, more RRSIGs are found
60238106Sdes * that sign the data as well, doubles are removed.
61238106Sdes */
62238106Sdes
63238106Sdes#ifndef UTIL_DATA_MSGPARSE_H
64238106Sdes#define UTIL_DATA_MSGPARSE_H
65238106Sdes#include "util/storage/lruhash.h"
66291767Sdes#include "sldns/pkthdr.h"
67291767Sdes#include "sldns/rrdef.h"
68269257Sdesstruct sldns_buffer;
69238106Sdesstruct rrset_parse;
70238106Sdesstruct rr_parse;
71238106Sdesstruct regional;
72238106Sdes
73238106Sdes/** number of buckets in parse rrset hash table. Must be power of 2. */
74238106Sdes#define PARSE_TABLE_SIZE 32
75238106Sdes/** Maximum TTL that is allowed. */
76269257Sdesextern time_t MAX_TTL;
77238106Sdes/** Minimum TTL that is allowed. */
78269257Sdesextern time_t MIN_TTL;
79291767Sdes/** Maximum Negative TTL that is allowed */
80291767Sdesextern time_t MAX_NEG_TTL;
81238106Sdes/** Negative cache time (for entries without any RRs.) */
82238106Sdes#define NORR_TTL 5 /* seconds */
83238106Sdes
84238106Sdes/**
85238106Sdes * Data stored in scratch pad memory during parsing.
86238106Sdes * Stores the data that will enter into the msgreply and packet result.
87238106Sdes */
88238106Sdesstruct msg_parse {
89238106Sdes	/** id from message, network format. */
90238106Sdes	uint16_t id;
91238106Sdes	/** flags from message, host format. */
92238106Sdes	uint16_t flags;
93238106Sdes	/** count of RRs, host format */
94238106Sdes	uint16_t qdcount;
95238106Sdes	/** count of RRs, host format */
96238106Sdes	uint16_t ancount;
97238106Sdes	/** count of RRs, host format */
98238106Sdes	uint16_t nscount;
99238106Sdes	/** count of RRs, host format */
100238106Sdes	uint16_t arcount;
101238106Sdes	/** count of RRsets per section. */
102238106Sdes	size_t an_rrsets;
103238106Sdes	/** count of RRsets per section. */
104238106Sdes	size_t ns_rrsets;
105238106Sdes	/** count of RRsets per section. */
106238106Sdes	size_t ar_rrsets;
107238106Sdes	/** total number of rrsets found. */
108238106Sdes	size_t rrset_count;
109238106Sdes
110238106Sdes	/** query dname (pointer to start location in packet, NULL if none */
111238106Sdes	uint8_t* qname;
112238106Sdes	/** length of query dname in octets, 0 if none */
113238106Sdes	size_t qname_len;
114238106Sdes	/** query type, host order. 0 if qdcount=0 */
115238106Sdes	uint16_t qtype;
116238106Sdes	/** query class, host order. 0 if qdcount=0 */
117238106Sdes	uint16_t qclass;
118238106Sdes
119238106Sdes	/**
120238106Sdes	 * Hash table array used during parsing to lookup rrset types.
121238106Sdes	 * Based on name, type, class.  Same hash value as in rrset cache.
122238106Sdes	 */
123238106Sdes	struct rrset_parse* hashtable[PARSE_TABLE_SIZE];
124238106Sdes
125238106Sdes	/** linked list of rrsets that have been found (in order). */
126238106Sdes	struct rrset_parse* rrset_first;
127238106Sdes	/** last element of rrset list. */
128238106Sdes	struct rrset_parse* rrset_last;
129238106Sdes};
130238106Sdes
131238106Sdes/**
132238106Sdes * Data stored for an rrset during parsing.
133238106Sdes */
134238106Sdesstruct rrset_parse {
135238106Sdes	/** next in hash bucket */
136238106Sdes	struct rrset_parse* rrset_bucket_next;
137238106Sdes	/** next in list of all rrsets */
138238106Sdes	struct rrset_parse* rrset_all_next;
139238106Sdes	/** hash value of rrset */
140238106Sdes	hashvalue_t hash;
141238106Sdes	/** which section was it found in: one of
142238106Sdes	 * LDNS_SECTION_ANSWER, LDNS_SECTION_AUTHORITY, LDNS_SECTION_ADDITIONAL
143238106Sdes	 */
144269257Sdes	sldns_pkt_section section;
145238106Sdes	/** start of (possibly compressed) dname in packet */
146238106Sdes	uint8_t* dname;
147238106Sdes	/** length of the dname uncompressed wireformat */
148238106Sdes	size_t dname_len;
149238106Sdes	/** type, host order. */
150238106Sdes	uint16_t type;
151238106Sdes	/** class, network order. var name so that it is not a c++ keyword. */
152238106Sdes	uint16_t rrset_class;
153238106Sdes	/** the flags for the rrset, like for packedrrset */
154238106Sdes	uint32_t flags;
155238106Sdes	/** number of RRs in the rr list */
156238106Sdes	size_t rr_count;
157238106Sdes	/** sum of RR rdata sizes */
158238106Sdes	size_t size;
159238106Sdes	/** linked list of RRs in this rrset. */
160238106Sdes	struct rr_parse* rr_first;
161238106Sdes	/** last in list of RRs in this rrset. */
162238106Sdes	struct rr_parse* rr_last;
163238106Sdes	/** number of RRSIGs over this rrset. */
164238106Sdes	size_t rrsig_count;
165238106Sdes	/** linked list of RRsig RRs over this rrset. */
166238106Sdes	struct rr_parse* rrsig_first;
167238106Sdes	/** last in list of RRSIG RRs over this rrset. */
168238106Sdes	struct rr_parse* rrsig_last;
169238106Sdes};
170238106Sdes
171238106Sdes/**
172238106Sdes * Data stored for an RR during parsing.
173238106Sdes */
174238106Sdesstruct rr_parse {
175238106Sdes	/**
176238106Sdes	 * Pointer to the RR. Points to start of TTL value in the packet.
177238106Sdes	 * Rdata length and rdata follow it.
178238106Sdes	 * its dname, type and class are the same and stored for the rrset.
179238106Sdes	 */
180238106Sdes	uint8_t* ttl_data;
181238106Sdes	/** true if ttl_data is not part of the packet, but elsewhere in mem.
182238106Sdes	 * Set for generated CNAMEs for DNAMEs. */
183238106Sdes	int outside_packet;
184238106Sdes	/** the length of the rdata if allocated (with no dname compression)*/
185238106Sdes	size_t size;
186238106Sdes	/** next in list of RRs. */
187238106Sdes	struct rr_parse* next;
188238106Sdes};
189238106Sdes
190238106Sdes/** Check if label length is first octet of a compression pointer, pass u8. */
191238106Sdes#define LABEL_IS_PTR(x) ( ((x)&0xc0) == 0xc0 )
192238106Sdes/** Calculate destination offset of a compression pointer. pass first and
193238106Sdes * second octets of the compression pointer. */
194238106Sdes#define PTR_OFFSET(x, y) ( ((x)&0x3f)<<8 | (y) )
195238106Sdes/** create a compression pointer to the given offset. */
196238106Sdes#define PTR_CREATE(offset) ((uint16_t)(0xc000 | (offset)))
197238106Sdes
198238106Sdes/** error codes, extended with EDNS, so > 15. */
199238106Sdes#define EDNS_RCODE_BADVERS	16	/** bad EDNS version */
200238106Sdes/** largest valid compression offset */
201238106Sdes#define PTR_MAX_OFFSET 	0x3fff
202238106Sdes
203238106Sdes/**
204238106Sdes * EDNS data storage
205238106Sdes * EDNS rdata is ignored.
206238106Sdes */
207238106Sdesstruct edns_data {
208238106Sdes	/** if EDNS OPT record was present */
209238106Sdes	int edns_present;
210238106Sdes	/** Extended RCODE */
211238106Sdes	uint8_t ext_rcode;
212238106Sdes	/** The EDNS version number */
213238106Sdes	uint8_t edns_version;
214238106Sdes	/** the EDNS bits field from ttl (host order): Z */
215238106Sdes	uint16_t bits;
216238106Sdes	/** UDP reassembly size. */
217238106Sdes	uint16_t udp_size;
218238106Sdes};
219238106Sdes
220238106Sdes/**
221238106Sdes * Obtain size in the packet of an rr type, that is before dname type.
222238106Sdes * Do TYPE_DNAME, and type STR, yourself. Gives size for most regular types.
223238106Sdes * @param rdf: the rdf type from the descriptor.
224238106Sdes * @return: size in octets. 0 on failure.
225238106Sdes */
226269257Sdessize_t get_rdf_size(sldns_rdf_type rdf);
227238106Sdes
228238106Sdes/**
229238106Sdes * Parse the packet.
230238106Sdes * @param pkt: packet, position at call must be at start of packet.
231238106Sdes *	at end position is after packet.
232238106Sdes * @param msg: where to store results.
233238106Sdes * @param region: how to alloc results.
234238106Sdes * @return: 0 if OK, or rcode on error.
235238106Sdes */
236269257Sdesint parse_packet(struct sldns_buffer* pkt, struct msg_parse* msg,
237238106Sdes	struct regional* region);
238238106Sdes
239238106Sdes/**
240238106Sdes * After parsing the packet, extract EDNS data from packet.
241238106Sdes * If not present this is noted in the data structure.
242238106Sdes * If a parse error happens, an error code is returned.
243238106Sdes *
244238106Sdes * Quirks:
245238106Sdes *	o ignores OPT rdata.
246238106Sdes *	o ignores OPT owner name.
247238106Sdes *	o ignores extra OPT records, except the last one in the packet.
248238106Sdes *
249238106Sdes * @param msg: parsed message structure. Modified on exit, if EDNS was present
250238106Sdes * 	it is removed from the additional section.
251238106Sdes * @param edns: the edns data is stored here. Does not have to be initialised.
252238106Sdes * @return: 0 on success. or an RCODE on an error.
253238106Sdes *	RCODE formerr if OPT in wrong section, and so on.
254238106Sdes */
255238106Sdesint parse_extract_edns(struct msg_parse* msg, struct edns_data* edns);
256238106Sdes
257238106Sdes/**
258238106Sdes * If EDNS data follows a query section, extract it and initialize edns struct.
259238106Sdes * @param pkt: the packet. position at start must be right after the query
260238106Sdes *	section. At end, right after EDNS data or no movement if failed.
261238106Sdes * @param edns: the edns data allocated by the caller. Does not have to be
262238106Sdes *	initialised.
263238106Sdes * @return: 0 on success, or an RCODE on error.
264238106Sdes *	RCODE formerr if OPT is badly formatted and so on.
265238106Sdes */
266269257Sdesint parse_edns_from_pkt(struct sldns_buffer* pkt, struct edns_data* edns);
267238106Sdes
268238106Sdes/**
269238106Sdes * Calculate hash value for rrset in packet.
270238106Sdes * @param pkt: the packet.
271238106Sdes * @param dname: pointer to uncompressed dname, or compressed dname in packet.
272238106Sdes * @param type: rrset type in host order.
273238106Sdes * @param dclass: rrset class in network order.
274238106Sdes * @param rrset_flags: rrset flags (same as packed_rrset flags).
275238106Sdes * @return hash value
276238106Sdes */
277269257Sdeshashvalue_t pkt_hash_rrset(struct sldns_buffer* pkt, uint8_t* dname, uint16_t type,
278238106Sdes        uint16_t dclass, uint32_t rrset_flags);
279238106Sdes
280238106Sdes/**
281238106Sdes * Lookup in msg hashtable to find a rrset.
282238106Sdes * @param msg: with the hashtable.
283238106Sdes * @param pkt: packet for compressed names.
284238106Sdes * @param h: hash value
285238106Sdes * @param rrset_flags: flags of rrset sought for.
286238106Sdes * @param dname: name of rrset sought for.
287238106Sdes * @param dnamelen: len of dname.
288238106Sdes * @param type: rrset type, host order.
289238106Sdes * @param dclass: rrset class, network order.
290238106Sdes * @return NULL or the rrset_parse if found.
291238106Sdes */
292238106Sdesstruct rrset_parse* msgparse_hashtable_lookup(struct msg_parse* msg,
293269257Sdes	struct sldns_buffer* pkt, hashvalue_t h, uint32_t rrset_flags,
294238106Sdes	uint8_t* dname, size_t dnamelen, uint16_t type, uint16_t dclass);
295238106Sdes
296238106Sdes/**
297238106Sdes * Remove rrset from hash table.
298238106Sdes * @param msg: with hashtable.
299238106Sdes * @param rrset: with hash value and id info.
300238106Sdes */
301238106Sdesvoid msgparse_bucket_remove(struct msg_parse* msg, struct rrset_parse* rrset);
302238106Sdes
303238106Sdes#endif /* UTIL_DATA_MSGPARSE_H */
304