2 * util/data/msgparse.h - parse wireformat DNS messages.
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37 * Contains message parsing data structures.
38 * These point back into the packet buffer.
40 * During parsing RRSIGS are put together with the rrsets they (claim to) sign.
41 * This process works as follows:
42 * o if RRSIG follows the data rrset, it is added to the rrset rrsig list.
43 * o if no matching data rrset is found, the RRSIG becomes a new rrset.
44 * o If the data rrset later follows the RRSIG
45 * o See if the RRSIG rrset contains multiple types, and needs to
46 * have the rrsig(s) for that data type split off.
47 * o Put the data rr as data type in the rrset and rrsig in list.
48 * o RRSIGs are allowed to move to a different section. The section of
49 * the data item is used for the final rrset.
50 * o multiple signatures over an RRset are possible.
52 * For queries of qtype=RRSIG, some special handling is needed, to avoid
53 * splitting the RRSIG in the answer section.
54 * o duplicate, not split, RRSIGs from the answer section, if qtype=RRSIG.
55 * o check for doubles in the rrsig list when adding an RRSIG to data,
56 * so that a data rrset is signed by RRSIGs with different rdata.
58 * This will move the RRSIG from the answer section to sign the data further
59 * in the packet (if possible). If then after that, more RRSIGs are found
60 * that sign the data as well, doubles are removed.
63 #ifndef UTIL_DATA_MSGPARSE_H
64 #define UTIL_DATA_MSGPARSE_H
65 #include "util/storage/lruhash.h"
66 #include "sldns/pkthdr.h"
67 #include "sldns/rrdef.h"
74 /** number of buckets in parse rrset hash table. Must be power of 2. */
75 #define PARSE_TABLE_SIZE 32
76 /** Maximum TTL that is allowed. */
77 extern time_t MAX_TTL;
78 /** Minimum TTL that is allowed. */
79 extern time_t MIN_TTL;
80 /** Maximum Negative TTL that is allowed */
81 extern time_t MAX_NEG_TTL;
82 /** Time to serve records after expiration */
83 extern time_t SERVE_EXPIRED_TTL;
84 /** Negative cache time (for entries without any RRs.) */
85 #define NORR_TTL 5 /* seconds */
88 * Data stored in scratch pad memory during parsing.
89 * Stores the data that will enter into the msgreply and packet result.
92 /** id from message, network format. */
94 /** flags from message, host format. */
96 /** count of RRs, host format */
98 /** count of RRs, host format */
100 /** count of RRs, host format */
102 /** count of RRs, host format */
104 /** count of RRsets per section. */
106 /** count of RRsets per section. */
108 /** count of RRsets per section. */
110 /** total number of rrsets found. */
113 /** query dname (pointer to start location in packet, NULL if none */
115 /** length of query dname in octets, 0 if none */
117 /** query type, host order. 0 if qdcount=0 */
119 /** query class, host order. 0 if qdcount=0 */
123 * Hash table array used during parsing to lookup rrset types.
124 * Based on name, type, class. Same hash value as in rrset cache.
126 struct rrset_parse* hashtable[PARSE_TABLE_SIZE];
128 /** linked list of rrsets that have been found (in order). */
129 struct rrset_parse* rrset_first;
130 /** last element of rrset list. */
131 struct rrset_parse* rrset_last;
135 * Data stored for an rrset during parsing.
138 /** next in hash bucket */
139 struct rrset_parse* rrset_bucket_next;
140 /** next in list of all rrsets */
141 struct rrset_parse* rrset_all_next;
142 /** hash value of rrset */
144 /** which section was it found in: one of
145 * LDNS_SECTION_ANSWER, LDNS_SECTION_AUTHORITY, LDNS_SECTION_ADDITIONAL
147 sldns_pkt_section section;
148 /** start of (possibly compressed) dname in packet */
150 /** length of the dname uncompressed wireformat */
152 /** type, host order. */
154 /** class, network order. var name so that it is not a c++ keyword. */
155 uint16_t rrset_class;
156 /** the flags for the rrset, like for packedrrset */
158 /** number of RRs in the rr list */
160 /** sum of RR rdata sizes */
162 /** linked list of RRs in this rrset. */
163 struct rr_parse* rr_first;
164 /** last in list of RRs in this rrset. */
165 struct rr_parse* rr_last;
166 /** number of RRSIGs over this rrset. */
168 /** linked list of RRsig RRs over this rrset. */
169 struct rr_parse* rrsig_first;
170 /** last in list of RRSIG RRs over this rrset. */
171 struct rr_parse* rrsig_last;
175 * Data stored for an RR during parsing.
179 * Pointer to the RR. Points to start of TTL value in the packet.
180 * Rdata length and rdata follow it.
181 * its dname, type and class are the same and stored for the rrset.
184 /** true if ttl_data is not part of the packet, but elsewhere in mem.
185 * Set for generated CNAMEs for DNAMEs. */
187 /** the length of the rdata if allocated (with no dname compression)*/
189 /** next in list of RRs. */
190 struct rr_parse* next;
193 /** Check if label length is first octet of a compression pointer, pass u8. */
194 #define LABEL_IS_PTR(x) ( ((x)&0xc0) == 0xc0 )
195 /** Calculate destination offset of a compression pointer. pass first and
196 * second octets of the compression pointer. */
197 #define PTR_OFFSET(x, y) ( ((x)&0x3f)<<8 | (y) )
198 /** create a compression pointer to the given offset. */
199 #define PTR_CREATE(offset) ((uint16_t)(0xc000 | (offset)))
201 /** error codes, extended with EDNS, so > 15. */
202 #define EDNS_RCODE_BADVERS 16 /** bad EDNS version */
203 /** largest valid compression offset */
204 #define PTR_MAX_OFFSET 0x3fff
208 * rdata is parsed in a list (has accessor functions). allocated in a
212 /** if EDNS OPT record was present */
214 /** Extended RCODE */
216 /** The EDNS version number */
217 uint8_t edns_version;
218 /** the EDNS bits field from ttl (host order): Z */
220 /** UDP reassembly size. */
222 /** rdata element list, or NULL if none */
223 struct edns_option* opt_list;
230 /** next item in list */
231 struct edns_option* next;
232 /** type of this edns option */
234 /** length of this edns option (cannot exceed uint16 in encoding) */
236 /** data of this edns option; allocated in region, or NULL if len=0 */
241 * Obtain size in the packet of an rr type, that is before dname type.
242 * Do TYPE_DNAME, and type STR, yourself. Gives size for most regular types.
243 * @param rdf: the rdf type from the descriptor.
244 * @return: size in octets. 0 on failure.
246 size_t get_rdf_size(sldns_rdf_type rdf);
250 * @param pkt: packet, position at call must be at start of packet.
251 * at end position is after packet.
252 * @param msg: where to store results.
253 * @param region: how to alloc results.
254 * @return: 0 if OK, or rcode on error.
256 int parse_packet(struct sldns_buffer* pkt, struct msg_parse* msg,
257 struct regional* region);
260 * After parsing the packet, extract EDNS data from packet.
261 * If not present this is noted in the data structure.
262 * If a parse error happens, an error code is returned.
265 * o ignores OPT rdata.
266 * o ignores OPT owner name.
267 * o ignores extra OPT records, except the last one in the packet.
269 * @param msg: parsed message structure. Modified on exit, if EDNS was present
270 * it is removed from the additional section.
271 * @param edns: the edns data is stored here. Does not have to be initialised.
272 * @param region: region to alloc results in (edns option contents)
273 * @return: 0 on success. or an RCODE on an error.
274 * RCODE formerr if OPT in wrong section, and so on.
276 int parse_extract_edns(struct msg_parse* msg, struct edns_data* edns,
277 struct regional* region);
280 * If EDNS data follows a query section, extract it and initialize edns struct.
281 * @param pkt: the packet. position at start must be right after the query
282 * section. At end, right after EDNS data or no movement if failed.
283 * @param edns: the edns data allocated by the caller. Does not have to be
285 * @param region: region to alloc results in (edns option contents)
286 * @return: 0 on success, or an RCODE on error.
287 * RCODE formerr if OPT is badly formatted and so on.
289 int parse_edns_from_pkt(struct sldns_buffer* pkt, struct edns_data* edns,
290 struct regional* region);
293 * Calculate hash value for rrset in packet.
294 * @param pkt: the packet.
295 * @param dname: pointer to uncompressed dname, or compressed dname in packet.
296 * @param type: rrset type in host order.
297 * @param dclass: rrset class in network order.
298 * @param rrset_flags: rrset flags (same as packed_rrset flags).
301 hashvalue_type pkt_hash_rrset(struct sldns_buffer* pkt, uint8_t* dname,
302 uint16_t type, uint16_t dclass, uint32_t rrset_flags);
305 * Lookup in msg hashtable to find a rrset.
306 * @param msg: with the hashtable.
307 * @param pkt: packet for compressed names.
308 * @param h: hash value
309 * @param rrset_flags: flags of rrset sought for.
310 * @param dname: name of rrset sought for.
311 * @param dnamelen: len of dname.
312 * @param type: rrset type, host order.
313 * @param dclass: rrset class, network order.
314 * @return NULL or the rrset_parse if found.
316 struct rrset_parse* msgparse_hashtable_lookup(struct msg_parse* msg,
317 struct sldns_buffer* pkt, hashvalue_type h, uint32_t rrset_flags,
318 uint8_t* dname, size_t dnamelen, uint16_t type, uint16_t dclass);
321 * Remove rrset from hash table.
322 * @param msg: with hashtable.
323 * @param rrset: with hash value and id info.
325 void msgparse_bucket_remove(struct msg_parse* msg, struct rrset_parse* rrset);
328 * Log the edns options in the edns option list.
329 * @param level: the verbosity level.
330 * @param info_str: the informational string to be printed before the options.
331 * @param list: the edns option list.
333 void log_edns_opt_list(enum verbosity_value level, const char* info_str,
334 struct edns_option* list);
336 #endif /* UTIL_DATA_MSGPARSE_H */