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3 (C) 2010, 2011, 2012 Christian Grothoff (and other contributing authors)
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22 * @file include/gnunet_dnsparser_lib.h
23 * @brief API for helper library to parse DNS packets.
24 * @author Philipp Toelke
25 * @author Christian Grothoff
27 #ifndef GNUNET_DNSPARSER_LIB_H
28 #define GNUNET_DNSPARSER_LIB_H
31 #include "gnunet_common.h"
34 * A few common DNS types.
36 #define GNUNET_DNSPARSER_TYPE_A 1
37 #define GNUNET_DNSPARSER_TYPE_NS 2
38 #define GNUNET_DNSPARSER_TYPE_CNAME 5
39 #define GNUNET_DNSPARSER_TYPE_SOA 6
40 #define GNUNET_DNSPARSER_TYPE_PTR 12
41 #define GNUNET_DNSPARSER_TYPE_MX 15
42 #define GNUNET_DNSPARSER_TYPE_TXT 16
43 #define GNUNET_DNSPARSER_TYPE_AAAA 28
44 #define GNUNET_DNSPARSER_TYPE_SRV 33
47 * A few common DNS classes (ok, only one is common, but I list a
48 * couple more to make it clear what we're talking about here).
50 #define GNUNET_DNSPARSER_CLASS_INTERNET 1
51 #define GNUNET_DNSPARSER_CLASS_CHAOS 3
52 #define GNUNET_DNSPARSER_CLASS_HESIOD 4
54 #define GNUNET_DNSPARSER_OPCODE_QUERY 0
55 #define GNUNET_DNSPARSER_OPCODE_INVERSE_QUERY 1
56 #define GNUNET_DNSPARSER_OPCODE_STATUS 2
61 #define GNUNET_DNSPARSER_RETURN_CODE_NO_ERROR 0
62 #define GNUNET_DNSPARSER_RETURN_CODE_FORMAT_ERROR 1
63 #define GNUNET_DNSPARSER_RETURN_CODE_SERVER_FAILURE 2
64 #define GNUNET_DNSPARSER_RETURN_CODE_NAME_ERROR 3
65 #define GNUNET_DNSPARSER_RETURN_CODE_NOT_IMPLEMENTED 4
66 #define GNUNET_DNSPARSER_RETURN_CODE_REFUSED 5
71 #define GNUNET_DNSPARSER_RETURN_CODE_YXDOMAIN 6
72 #define GNUNET_DNSPARSER_RETURN_CODE_YXRRSET 7
73 #define GNUNET_DNSPARSER_RETURN_CODE_NXRRSET 8
74 #define GNUNET_DNSPARSER_RETURN_CODE_NOT_AUTH 9
75 #define GNUNET_DNSPARSER_RETURN_CODE_NOT_ZONE 10
78 * DNS flags (largely RFC 1035 / RFC 2136).
80 struct GNUNET_DNSPARSER_Flags
83 * Set to 1 if recursion is desired (client -> server)
85 unsigned int recursion_desired : 1 GNUNET_PACKED;
88 * Set to 1 if message is truncated
90 unsigned int message_truncated : 1 GNUNET_PACKED;
93 * Set to 1 if this is an authoritative answer
95 unsigned int authoritative_answer : 1 GNUNET_PACKED;
98 * See GNUNET_DNSPARSER_OPCODE_ defines.
100 unsigned int opcode : 4 GNUNET_PACKED;
103 * query:0, response:1
105 unsigned int query_or_response : 1 GNUNET_PACKED;
108 * See GNUNET_DNSPARSER_RETURN_CODE_ defines.
110 unsigned int return_code : 4 GNUNET_PACKED;
115 unsigned int checking_disabled : 1 GNUNET_PACKED;
118 * Response has been cryptographically verified, RFC 4035.
120 unsigned int authenticated_data : 1 GNUNET_PACKED;
125 unsigned int zero : 1 GNUNET_PACKED;
128 * Set to 1 if recursion is available (server -> client)
130 unsigned int recursion_available : 1 GNUNET_PACKED;
132 } GNUNET_GCC_STRUCT_LAYOUT;
138 struct GNUNET_DNSPARSER_Query
142 * Name of the record that the query is for (0-terminated).
147 * See GNUNET_DNSPARSER_TYPE_*.
152 * See GNUNET_DNSPARSER_CLASS_*.
160 * Information from MX records (RFC 1035).
162 struct GNUNET_DNSPARSER_MxRecord
166 * Preference for this entry (lower value is higher preference).
171 * Name of the mail server.
179 * Information from SRV records (RFC 2782). The 'service', 'proto'
180 * and 'domain_name' fields together give the DNS-name which for SRV
181 * records is of the form "_$SERVICE._$PROTO.$DOMAIN_NAME". The DNS
182 * parser provides the full name in 'struct DNSPARSER_Record' and the
183 * individual components in the respective fields of this struct.
184 * When serializing, you CAN set the 'name' field of 'struct
185 * GNUNET_DNSPARSER_Record' to NULL, in which case the DNSPARSER code
186 * will populate 'name' from the 'service', 'proto' and 'domain_name'
187 * fields in this struct.
189 struct GNUNET_DNSPARSER_SrvRecord
193 * Service name without the underscore (!). Note that RFC 6335 clarifies the
194 * set of legal characters for service names.
199 * Transport protocol (typcially "tcp" or "udp", but others might be allowed).
200 * Without the underscore (!).
205 * Domain name for which the record is valid
210 * Hostname offering the service.
215 * Preference for this entry (lower value is higher preference). Clients
216 * will contact hosts from the lowest-priority group first and fall back
217 * to higher priorities if the low-priority entries are unavailable.
222 * Relative weight for records with the same priority. Clients will use
223 * the hosts of the same (lowest) priority with a probability proportional
224 * to the weight given.
229 * TCP or UDP port of the service.
237 * Information from SOA records (RFC 1035).
239 struct GNUNET_DNSPARSER_SoaRecord
243 *The domainname of the name server that was the
244 * original or primary source of data for this zone.
249 * A domainname which specifies the mailbox of the
250 * person responsible for this zone.
255 * The version number of the original copy of the zone.
260 * Time interval before the zone should be refreshed.
265 * Time interval that should elapse before a failed refresh should
271 * Time value that specifies the upper limit on the time interval
272 * that can elapse before the zone is no longer authoritative.
277 * The bit minimum TTL field that should be exported with any RR
280 uint32_t minimum_ttl;
286 * Binary record information (unparsed).
288 struct GNUNET_DNSPARSER_RawRecord
292 * Binary record data.
297 * Number of bytes in data.
304 * A DNS response record.
306 struct GNUNET_DNSPARSER_Record
310 * Name of the record that the query is for (0-terminated).
315 * Payload of the record (which one of these is valid depends on the 'type').
321 * For NS, CNAME and PTR records, this is the uncompressed 0-terminated hostname.
326 * SOA data for SOA records.
328 struct GNUNET_DNSPARSER_SoaRecord *soa;
331 * MX data for MX records.
333 struct GNUNET_DNSPARSER_MxRecord *mx;
336 * SRV data for SRV records.
338 struct GNUNET_DNSPARSER_SrvRecord *srv;
341 * Raw data for all other types.
343 struct GNUNET_DNSPARSER_RawRecord raw;
349 * When does the record expire?
351 struct GNUNET_TIME_Absolute expiration_time;
354 * See GNUNET_DNSPARSER_TYPE_*.
359 * See GNUNET_DNSPARSER_CLASS_*.
367 * Easy-to-process, parsed version of a DNS packet.
369 struct GNUNET_DNSPARSER_Packet
372 * Array of all queries in the packet, must contain "num_queries" entries.
374 struct GNUNET_DNSPARSER_Query *queries;
377 * Array of all answers in the packet, must contain "num_answers" entries.
379 struct GNUNET_DNSPARSER_Record *answers;
382 * Array of all authority records in the packet, must contain "num_authority_records" entries.
384 struct GNUNET_DNSPARSER_Record *authority_records;
387 * Array of all additional answers in the packet, must contain "num_additional_records" entries.
389 struct GNUNET_DNSPARSER_Record *additional_records;
392 * Number of queries in the packet.
394 unsigned int num_queries;
397 * Number of answers in the packet, should be 0 for queries.
399 unsigned int num_answers;
402 * Number of authoritative answers in the packet, should be 0 for queries.
404 unsigned int num_authority_records;
407 * Number of additional records in the packet, should be 0 for queries.
409 unsigned int num_additional_records;
412 * Bitfield of DNS flags.
414 struct GNUNET_DNSPARSER_Flags flags;
417 * DNS ID (to match replies to requests).
425 * Parse a UDP payload of a DNS packet in to a nice struct for further
426 * processing and manipulation.
428 * @param udp_payload wire-format of the DNS packet
429 * @param udp_payload_length number of bytes in udp_payload
430 * @return NULL on error, otherwise the parsed packet
432 struct GNUNET_DNSPARSER_Packet *
433 GNUNET_DNSPARSER_parse (const char *udp_payload,
434 size_t udp_payload_length);
438 * Free memory taken by a packet.
440 * @param p packet to free
443 GNUNET_DNSPARSER_free_packet (struct GNUNET_DNSPARSER_Packet *p);
447 * Given a DNS packet, generate the corresponding UDP payload.
449 * @param p packet to pack
450 * @param max maximum allowed size for the resulting UDP payload
451 * @param buf set to a buffer with the packed message
452 * @param buf_length set to the length of buf
453 * @return GNUNET_SYSERR if 'p' is invalid
454 * GNUNET_NO if 'p' was truncated (but there is still a result in 'buf')
455 * GNUNET_OK if 'p' was packed completely into '*buf'
458 GNUNET_DNSPARSER_pack (const struct GNUNET_DNSPARSER_Packet *p,