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"
77 /** number of buckets in parse rrset hash table. Must be power of 2. */
78 #define PARSE_TABLE_SIZE 32
79 /** Maximum TTL that is allowed. */
80 extern time_t MAX_TTL;
81 /** Minimum TTL that is allowed. */
82 extern time_t MIN_TTL;
83 /** Maximum Negative TTL that is allowed */
84 extern time_t MAX_NEG_TTL;
85 /** If we serve expired entries and prefetch them */
86 extern int SERVE_EXPIRED;
87 /** Time to serve records after expiration */
88 extern time_t SERVE_EXPIRED_TTL;
89 /** TTL to use for expired records */
90 extern time_t SERVE_EXPIRED_REPLY_TTL;
91 /** Negative cache time (for entries without any RRs.) */
92 #define NORR_TTL 5 /* seconds */
93 /** If we serve the original TTL or decrementing TTLs */
94 extern int SERVE_ORIGINAL_TTL;
97 * Data stored in scratch pad memory during parsing.
98 * Stores the data that will enter into the msgreply and packet result.
101 /** id from message, network format. */
103 /** flags from message, host format. */
105 /** count of RRs, host format */
107 /** count of RRs, host format */
109 /** count of RRs, host format */
111 /** count of RRs, host format */
113 /** count of RRsets per section. */
115 /** count of RRsets per section. */
117 /** count of RRsets per section. */
119 /** total number of rrsets found. */
122 /** query dname (pointer to start location in packet, NULL if none */
124 /** length of query dname in octets, 0 if none */
126 /** query type, host order. 0 if qdcount=0 */
128 /** query class, host order. 0 if qdcount=0 */
132 * Hash table array used during parsing to lookup rrset types.
133 * Based on name, type, class. Same hash value as in rrset cache.
135 struct rrset_parse* hashtable[PARSE_TABLE_SIZE];
137 /** linked list of rrsets that have been found (in order). */
138 struct rrset_parse* rrset_first;
139 /** last element of rrset list. */
140 struct rrset_parse* rrset_last;
144 * Data stored for an rrset during parsing.
147 /** next in hash bucket */
148 struct rrset_parse* rrset_bucket_next;
149 /** next in list of all rrsets */
150 struct rrset_parse* rrset_all_next;
151 /** hash value of rrset */
153 /** which section was it found in: one of
154 * LDNS_SECTION_ANSWER, LDNS_SECTION_AUTHORITY, LDNS_SECTION_ADDITIONAL
156 sldns_pkt_section section;
157 /** start of (possibly compressed) dname in packet */
159 /** length of the dname uncompressed wireformat */
161 /** type, host order. */
163 /** class, network order. var name so that it is not a c++ keyword. */
164 uint16_t rrset_class;
165 /** the flags for the rrset, like for packedrrset */
167 /** number of RRs in the rr list */
169 /** sum of RR rdata sizes */
171 /** linked list of RRs in this rrset. */
172 struct rr_parse* rr_first;
173 /** last in list of RRs in this rrset. */
174 struct rr_parse* rr_last;
175 /** number of RRSIGs over this rrset. */
177 /** linked list of RRsig RRs over this rrset. */
178 struct rr_parse* rrsig_first;
179 /** last in list of RRSIG RRs over this rrset. */
180 struct rr_parse* rrsig_last;
184 * Data stored for an RR during parsing.
188 * Pointer to the RR. Points to start of TTL value in the packet.
189 * Rdata length and rdata follow it.
190 * its dname, type and class are the same and stored for the rrset.
193 /** true if ttl_data is not part of the packet, but elsewhere in mem.
194 * Set for generated CNAMEs for DNAMEs. */
196 /** the length of the rdata if allocated (with no dname compression)*/
198 /** next in list of RRs. */
199 struct rr_parse* next;
202 /** Check if label length is first octet of a compression pointer, pass u8. */
203 #define LABEL_IS_PTR(x) ( ((x)&0xc0) == 0xc0 )
204 /** Calculate destination offset of a compression pointer. pass first and
205 * second octets of the compression pointer. */
206 #define PTR_OFFSET(x, y) ( ((x)&0x3f)<<8 | (y) )
207 /** create a compression pointer to the given offset. */
208 #define PTR_CREATE(offset) ((uint16_t)(0xc000 | (offset)))
210 /** error codes, extended with EDNS, so > 15. */
211 #define EDNS_RCODE_BADVERS 16 /** bad EDNS version */
212 /** largest valid compression offset */
213 #define PTR_MAX_OFFSET 0x3fff
217 * rdata is parsed in a list (has accessor functions). allocated in a
221 /** Extended RCODE */
223 /** The EDNS version number */
224 uint8_t edns_version;
225 /** the EDNS bits field from ttl (host order): Z */
227 /** UDP reassembly size. */
229 /** rdata element list of options of an incoming packet created at
230 * parse time, or NULL if none */
231 struct edns_option* opt_list_in;
232 /** rdata element list of options to encode for outgoing packets,
234 struct edns_option* opt_list_out;
235 /** rdata element list of outgoing edns options from modules
237 struct edns_option* opt_list_inplace_cb_out;
238 /** block size to pad */
239 uint16_t padding_block_size;
240 /** if EDNS OPT record was present */
241 unsigned int edns_present : 1;
242 /** if a cookie was present */
243 unsigned int cookie_present : 1;
244 /** if the cookie validated */
245 unsigned int cookie_valid : 1;
246 /** if the cookie holds only the client part */
247 unsigned int cookie_client : 1;
254 /** next item in list */
255 struct edns_option* next;
256 /** type of this edns option */
258 /** length of this edns option (cannot exceed uint16 in encoding) */
260 /** data of this edns option; allocated in region, or NULL if len=0 */
265 * Obtain size in the packet of an rr type, that is before dname type.
266 * Do TYPE_DNAME, and type STR, yourself. Gives size for most regular types.
267 * @param rdf: the rdf type from the descriptor.
268 * @return: size in octets. 0 on failure.
270 size_t get_rdf_size(sldns_rdf_type rdf);
274 * @param pkt: packet, position at call must be at start of packet.
275 * at end position is after packet.
276 * @param msg: where to store results.
277 * @param region: how to alloc results.
278 * @return: 0 if OK, or rcode on error.
280 int parse_packet(struct sldns_buffer* pkt, struct msg_parse* msg,
281 struct regional* region);
284 * After parsing the packet, extract EDNS data from packet.
285 * If not present this is noted in the data structure.
286 * If a parse error happens, an error code is returned.
289 * o ignores OPT rdata.
290 * o ignores OPT owner name.
291 * o ignores extra OPT records, except the last one in the packet.
293 * @param msg: parsed message structure. Modified on exit, if EDNS was present
294 * it is removed from the additional section.
295 * @param edns: the edns data is stored here. Does not have to be initialised.
296 * @param region: region to alloc results in (edns option contents)
297 * @return: 0 on success. or an RCODE on an error.
298 * RCODE formerr if OPT in wrong section, and so on.
300 int parse_extract_edns_from_response_msg(struct msg_parse* msg,
301 struct edns_data* edns, struct regional* region);
304 * Skip RRs from packet
305 * @param pkt: the packet. position at start must be right after the query
306 * section. At end, right after EDNS data or no movement if failed.
307 * @param num: Limit of the number of records we want to parse.
308 * @return: 0 on success, 1 on failure.
310 int skip_pkt_rrs(struct sldns_buffer* pkt, int num);
313 * If EDNS data follows a query section, extract it and initialize edns struct.
314 * @param pkt: the packet. position at start must be right after the query
315 * section. At end, right after EDNS data or no movement if failed.
316 * @param edns: the edns data allocated by the caller. Does not have to be
318 * @param cfg: the configuration (with nsid value etc.)
319 * @param c: commpoint to determine transport (if needed)
320 * @param repinfo: commreply to determine the client address
321 * @param now: current time
322 * @param region: region to alloc results in (edns option contents)
323 * @return: 0 on success, or an RCODE on error.
324 * RCODE formerr if OPT is badly formatted and so on.
326 int parse_edns_from_query_pkt(struct sldns_buffer* pkt, struct edns_data* edns,
327 struct config_file* cfg, struct comm_point* c,
328 struct comm_reply* repinfo, time_t now, struct regional* region);
331 * Calculate hash value for rrset in packet.
332 * @param pkt: the packet.
333 * @param dname: pointer to uncompressed dname, or compressed dname in packet.
334 * @param type: rrset type in host order.
335 * @param dclass: rrset class in network order.
336 * @param rrset_flags: rrset flags (same as packed_rrset flags).
339 hashvalue_type pkt_hash_rrset(struct sldns_buffer* pkt, uint8_t* dname,
340 uint16_t type, uint16_t dclass, uint32_t rrset_flags);
343 * Lookup in msg hashtable to find a rrset.
344 * @param msg: with the hashtable.
345 * @param pkt: packet for compressed names.
346 * @param h: hash value
347 * @param rrset_flags: flags of rrset sought for.
348 * @param dname: name of rrset sought for.
349 * @param dnamelen: len of dname.
350 * @param type: rrset type, host order.
351 * @param dclass: rrset class, network order.
352 * @return NULL or the rrset_parse if found.
354 struct rrset_parse* msgparse_hashtable_lookup(struct msg_parse* msg,
355 struct sldns_buffer* pkt, hashvalue_type h, uint32_t rrset_flags,
356 uint8_t* dname, size_t dnamelen, uint16_t type, uint16_t dclass);
359 * Remove rrset from hash table.
360 * @param msg: with hashtable.
361 * @param rrset: with hash value and id info.
363 void msgparse_bucket_remove(struct msg_parse* msg, struct rrset_parse* rrset);
366 * Log the edns options in the edns option list.
367 * @param level: the verbosity level.
368 * @param info_str: the informational string to be printed before the options.
369 * @param list: the edns option list.
371 void log_edns_opt_list(enum verbosity_value level, const char* info_str,
372 struct edns_option* list);
374 #endif /* UTIL_DATA_MSGPARSE_H */