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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
45 #define GNUNET_DNSPARSER_TYPE_TLSA 52
48 * A few common DNS classes (ok, only one is common, but I list a
49 * couple more to make it clear what we're talking about here).
51 #define GNUNET_DNSPARSER_CLASS_INTERNET 1
52 #define GNUNET_DNSPARSER_CLASS_CHAOS 3
53 #define GNUNET_DNSPARSER_CLASS_HESIOD 4
55 #define GNUNET_DNSPARSER_OPCODE_QUERY 0
56 #define GNUNET_DNSPARSER_OPCODE_INVERSE_QUERY 1
57 #define GNUNET_DNSPARSER_OPCODE_STATUS 2
62 #define GNUNET_DNSPARSER_RETURN_CODE_NO_ERROR 0
63 #define GNUNET_DNSPARSER_RETURN_CODE_FORMAT_ERROR 1
64 #define GNUNET_DNSPARSER_RETURN_CODE_SERVER_FAILURE 2
65 #define GNUNET_DNSPARSER_RETURN_CODE_NAME_ERROR 3
66 #define GNUNET_DNSPARSER_RETURN_CODE_NOT_IMPLEMENTED 4
67 #define GNUNET_DNSPARSER_RETURN_CODE_REFUSED 5
72 #define GNUNET_DNSPARSER_RETURN_CODE_YXDOMAIN 6
73 #define GNUNET_DNSPARSER_RETURN_CODE_YXRRSET 7
74 #define GNUNET_DNSPARSER_RETURN_CODE_NXRRSET 8
75 #define GNUNET_DNSPARSER_RETURN_CODE_NOT_AUTH 9
76 #define GNUNET_DNSPARSER_RETURN_CODE_NOT_ZONE 10
79 * DNS flags (largely RFC 1035 / RFC 2136).
81 struct GNUNET_DNSPARSER_Flags
83 #if __BYTE_ORDER == __LITTLE_ENDIAN
85 * Set to 1 if recursion is desired (client -> server)
87 unsigned int recursion_desired : 1 GNUNET_PACKED;
90 * Set to 1 if message is truncated
92 unsigned int message_truncated : 1 GNUNET_PACKED;
95 * Set to 1 if this is an authoritative answer
97 unsigned int authoritative_answer : 1 GNUNET_PACKED;
100 * See GNUNET_DNSPARSER_OPCODE_ defines.
102 unsigned int opcode : 4 GNUNET_PACKED;
105 * query:0, response:1
107 unsigned int query_or_response : 1 GNUNET_PACKED;
110 * See GNUNET_DNSPARSER_RETURN_CODE_ defines.
112 unsigned int return_code : 4 GNUNET_PACKED;
117 unsigned int checking_disabled : 1 GNUNET_PACKED;
120 * Response has been cryptographically verified, RFC 4035.
122 unsigned int authenticated_data : 1 GNUNET_PACKED;
127 unsigned int zero : 1 GNUNET_PACKED;
130 * Set to 1 if recursion is available (server -> client)
132 unsigned int recursion_available : 1 GNUNET_PACKED;
133 #elif __BYTE_ORDER == __BIG_ENDIAN
136 * query:0, response:1
138 unsigned int query_or_response : 1 GNUNET_PACKED;
141 * See GNUNET_DNSPARSER_OPCODE_ defines.
143 unsigned int opcode : 4 GNUNET_PACKED;
146 * Set to 1 if this is an authoritative answer
148 unsigned int authoritative_answer : 1 GNUNET_PACKED;
151 * Set to 1 if message is truncated
153 unsigned int message_truncated : 1 GNUNET_PACKED;
156 * Set to 1 if recursion is desired (client -> server)
158 unsigned int recursion_desired : 1 GNUNET_PACKED;
162 * Set to 1 if recursion is available (server -> client)
164 unsigned int recursion_available : 1 GNUNET_PACKED;
169 unsigned int zero : 1 GNUNET_PACKED;
172 * Response has been cryptographically verified, RFC 4035.
174 unsigned int authenticated_data : 1 GNUNET_PACKED;
179 unsigned int checking_disabled : 1 GNUNET_PACKED;
182 * See GNUNET_DNSPARSER_RETURN_CODE_ defines.
184 unsigned int return_code : 4 GNUNET_PACKED;
186 #error byteorder undefined
189 } GNUNET_GCC_STRUCT_LAYOUT;
195 struct GNUNET_DNSPARSER_Query
199 * Name of the record that the query is for (0-terminated).
204 * See GNUNET_DNSPARSER_TYPE_*.
209 * See GNUNET_DNSPARSER_CLASS_*.
217 * Information from MX records (RFC 1035).
219 struct GNUNET_DNSPARSER_MxRecord
223 * Preference for this entry (lower value is higher preference).
228 * Name of the mail server.
236 * Information from SRV records (RFC 2782). The 'service', 'proto'
237 * and 'domain_name' fields together give the DNS-name which for SRV
238 * records is of the form "_$SERVICE._$PROTO.$DOMAIN_NAME". The DNS
239 * parser provides the full name in 'struct DNSPARSER_Record' and the
240 * individual components in the respective fields of this struct.
241 * When serializing, you CAN set the 'name' field of 'struct
242 * GNUNET_DNSPARSER_Record' to NULL, in which case the DNSPARSER code
243 * will populate 'name' from the 'service', 'proto' and 'domain_name'
244 * fields in this struct.
246 struct GNUNET_DNSPARSER_SrvRecord
250 * Service name without the underscore (!). Note that RFC 6335 clarifies the
251 * set of legal characters for service names.
256 * Transport protocol (typcially "tcp" or "udp", but others might be allowed).
257 * Without the underscore (!).
262 * Domain name for which the record is valid
267 * Hostname offering the service.
272 * Preference for this entry (lower value is higher preference). Clients
273 * will contact hosts from the lowest-priority group first and fall back
274 * to higher priorities if the low-priority entries are unavailable.
279 * Relative weight for records with the same priority. Clients will use
280 * the hosts of the same (lowest) priority with a probability proportional
281 * to the weight given.
286 * TCP or UDP port of the service.
294 * Information from SOA records (RFC 1035).
296 struct GNUNET_DNSPARSER_SoaRecord
300 *The domainname of the name server that was the
301 * original or primary source of data for this zone.
306 * A domainname which specifies the mailbox of the
307 * person responsible for this zone.
312 * The version number of the original copy of the zone.
317 * Time interval before the zone should be refreshed.
322 * Time interval that should elapse before a failed refresh should
328 * Time value that specifies the upper limit on the time interval
329 * that can elapse before the zone is no longer authoritative.
334 * The bit minimum TTL field that should be exported with any RR
337 uint32_t minimum_ttl;
343 * Binary record information (unparsed).
345 struct GNUNET_DNSPARSER_RawRecord
349 * Binary record data.
354 * Number of bytes in data.
361 * A DNS response record.
363 struct GNUNET_DNSPARSER_Record
367 * Name of the record that the query is for (0-terminated).
372 * Payload of the record (which one of these is valid depends on the 'type').
378 * For NS, CNAME and PTR records, this is the uncompressed 0-terminated hostname.
383 * SOA data for SOA records.
385 struct GNUNET_DNSPARSER_SoaRecord *soa;
388 * MX data for MX records.
390 struct GNUNET_DNSPARSER_MxRecord *mx;
393 * SRV data for SRV records.
395 struct GNUNET_DNSPARSER_SrvRecord *srv;
398 * Raw data for all other types.
400 struct GNUNET_DNSPARSER_RawRecord raw;
406 * When does the record expire?
408 struct GNUNET_TIME_Absolute expiration_time;
411 * See GNUNET_DNSPARSER_TYPE_*.
416 * See GNUNET_DNSPARSER_CLASS_*.
424 * Easy-to-process, parsed version of a DNS packet.
426 struct GNUNET_DNSPARSER_Packet
429 * Array of all queries in the packet, must contain "num_queries" entries.
431 struct GNUNET_DNSPARSER_Query *queries;
434 * Array of all answers in the packet, must contain "num_answers" entries.
436 struct GNUNET_DNSPARSER_Record *answers;
439 * Array of all authority records in the packet, must contain "num_authority_records" entries.
441 struct GNUNET_DNSPARSER_Record *authority_records;
444 * Array of all additional answers in the packet, must contain "num_additional_records" entries.
446 struct GNUNET_DNSPARSER_Record *additional_records;
449 * Number of queries in the packet.
451 unsigned int num_queries;
454 * Number of answers in the packet, should be 0 for queries.
456 unsigned int num_answers;
459 * Number of authoritative answers in the packet, should be 0 for queries.
461 unsigned int num_authority_records;
464 * Number of additional records in the packet, should be 0 for queries.
466 unsigned int num_additional_records;
469 * Bitfield of DNS flags.
471 struct GNUNET_DNSPARSER_Flags flags;
474 * DNS ID (to match replies to requests).
482 * Parse a UDP payload of a DNS packet in to a nice struct for further
483 * processing and manipulation.
485 * @param udp_payload wire-format of the DNS packet
486 * @param udp_payload_length number of bytes in udp_payload
487 * @return NULL on error, otherwise the parsed packet
489 struct GNUNET_DNSPARSER_Packet *
490 GNUNET_DNSPARSER_parse (const char *udp_payload,
491 size_t udp_payload_length);
495 * Free memory taken by a packet.
497 * @param p packet to free
500 GNUNET_DNSPARSER_free_packet (struct GNUNET_DNSPARSER_Packet *p);
504 * Given a DNS packet, generate the corresponding UDP payload.
506 * @param p packet to pack
507 * @param max maximum allowed size for the resulting UDP payload
508 * @param buf set to a buffer with the packed message
509 * @param buf_length set to the length of buf
510 * @return GNUNET_SYSERR if 'p' is invalid
511 * GNUNET_NO if 'p' was truncated (but there is still a result in 'buf')
512 * GNUNET_OK if 'p' was packed completely into '*buf'
515 GNUNET_DNSPARSER_pack (const struct GNUNET_DNSPARSER_Packet *p,