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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
82 #if __BYTE_ORDER == __LITTLE_ENDIAN
84 * Set to 1 if recursion is desired (client -> server)
86 unsigned int recursion_desired : 1 GNUNET_PACKED;
89 * Set to 1 if message is truncated
91 unsigned int message_truncated : 1 GNUNET_PACKED;
94 * Set to 1 if this is an authoritative answer
96 unsigned int authoritative_answer : 1 GNUNET_PACKED;
99 * See GNUNET_DNSPARSER_OPCODE_ defines.
101 unsigned int opcode : 4 GNUNET_PACKED;
104 * query:0, response:1
106 unsigned int query_or_response : 1 GNUNET_PACKED;
109 * See GNUNET_DNSPARSER_RETURN_CODE_ defines.
111 unsigned int return_code : 4 GNUNET_PACKED;
116 unsigned int checking_disabled : 1 GNUNET_PACKED;
119 * Response has been cryptographically verified, RFC 4035.
121 unsigned int authenticated_data : 1 GNUNET_PACKED;
126 unsigned int zero : 1 GNUNET_PACKED;
129 * Set to 1 if recursion is available (server -> client)
131 unsigned int recursion_available : 1 GNUNET_PACKED;
132 #elif __BYTE_ORDER == __BIG_ENDIAN
135 * query:0, response:1
137 unsigned int query_or_response : 1 GNUNET_PACKED;
140 * See GNUNET_DNSPARSER_OPCODE_ defines.
142 unsigned int opcode : 4 GNUNET_PACKED;
145 * Set to 1 if this is an authoritative answer
147 unsigned int authoritative_answer : 1 GNUNET_PACKED;
150 * Set to 1 if message is truncated
152 unsigned int message_truncated : 1 GNUNET_PACKED;
155 * Set to 1 if recursion is desired (client -> server)
157 unsigned int recursion_desired : 1 GNUNET_PACKED;
161 * Set to 1 if recursion is available (server -> client)
163 unsigned int recursion_available : 1 GNUNET_PACKED;
168 unsigned int zero : 1 GNUNET_PACKED;
171 * Response has been cryptographically verified, RFC 4035.
173 unsigned int authenticated_data : 1 GNUNET_PACKED;
178 unsigned int checking_disabled : 1 GNUNET_PACKED;
181 * See GNUNET_DNSPARSER_RETURN_CODE_ defines.
183 unsigned int return_code : 4 GNUNET_PACKED;
185 #error byteorder undefined
188 } GNUNET_GCC_STRUCT_LAYOUT;
194 struct GNUNET_DNSPARSER_Query
198 * Name of the record that the query is for (0-terminated).
203 * See GNUNET_DNSPARSER_TYPE_*.
208 * See GNUNET_DNSPARSER_CLASS_*.
216 * Information from MX records (RFC 1035).
218 struct GNUNET_DNSPARSER_MxRecord
222 * Preference for this entry (lower value is higher preference).
227 * Name of the mail server.
235 * Information from SRV records (RFC 2782). The 'service', 'proto'
236 * and 'domain_name' fields together give the DNS-name which for SRV
237 * records is of the form "_$SERVICE._$PROTO.$DOMAIN_NAME". The DNS
238 * parser provides the full name in 'struct DNSPARSER_Record' and the
239 * individual components in the respective fields of this struct.
240 * When serializing, you CAN set the 'name' field of 'struct
241 * GNUNET_DNSPARSER_Record' to NULL, in which case the DNSPARSER code
242 * will populate 'name' from the 'service', 'proto' and 'domain_name'
243 * fields in this struct.
245 struct GNUNET_DNSPARSER_SrvRecord
249 * Service name without the underscore (!). Note that RFC 6335 clarifies the
250 * set of legal characters for service names.
255 * Transport protocol (typcially "tcp" or "udp", but others might be allowed).
256 * Without the underscore (!).
261 * Domain name for which the record is valid
266 * Hostname offering the service.
271 * Preference for this entry (lower value is higher preference). Clients
272 * will contact hosts from the lowest-priority group first and fall back
273 * to higher priorities if the low-priority entries are unavailable.
278 * Relative weight for records with the same priority. Clients will use
279 * the hosts of the same (lowest) priority with a probability proportional
280 * to the weight given.
285 * TCP or UDP port of the service.
293 * Information from SOA records (RFC 1035).
295 struct GNUNET_DNSPARSER_SoaRecord
299 *The domainname of the name server that was the
300 * original or primary source of data for this zone.
305 * A domainname which specifies the mailbox of the
306 * person responsible for this zone.
311 * The version number of the original copy of the zone.
316 * Time interval before the zone should be refreshed.
321 * Time interval that should elapse before a failed refresh should
327 * Time value that specifies the upper limit on the time interval
328 * that can elapse before the zone is no longer authoritative.
333 * The bit minimum TTL field that should be exported with any RR
336 uint32_t minimum_ttl;
342 * Binary record information (unparsed).
344 struct GNUNET_DNSPARSER_RawRecord
348 * Binary record data.
353 * Number of bytes in data.
360 * A DNS response record.
362 struct GNUNET_DNSPARSER_Record
366 * Name of the record that the query is for (0-terminated).
371 * Payload of the record (which one of these is valid depends on the 'type').
377 * For NS, CNAME and PTR records, this is the uncompressed 0-terminated hostname.
382 * SOA data for SOA records.
384 struct GNUNET_DNSPARSER_SoaRecord *soa;
387 * MX data for MX records.
389 struct GNUNET_DNSPARSER_MxRecord *mx;
392 * SRV data for SRV records.
394 struct GNUNET_DNSPARSER_SrvRecord *srv;
397 * Raw data for all other types.
399 struct GNUNET_DNSPARSER_RawRecord raw;
405 * When does the record expire?
407 struct GNUNET_TIME_Absolute expiration_time;
410 * See GNUNET_DNSPARSER_TYPE_*.
415 * See GNUNET_DNSPARSER_CLASS_*.
423 * Easy-to-process, parsed version of a DNS packet.
425 struct GNUNET_DNSPARSER_Packet
428 * Array of all queries in the packet, must contain "num_queries" entries.
430 struct GNUNET_DNSPARSER_Query *queries;
433 * Array of all answers in the packet, must contain "num_answers" entries.
435 struct GNUNET_DNSPARSER_Record *answers;
438 * Array of all authority records in the packet, must contain "num_authority_records" entries.
440 struct GNUNET_DNSPARSER_Record *authority_records;
443 * Array of all additional answers in the packet, must contain "num_additional_records" entries.
445 struct GNUNET_DNSPARSER_Record *additional_records;
448 * Number of queries in the packet.
450 unsigned int num_queries;
453 * Number of answers in the packet, should be 0 for queries.
455 unsigned int num_answers;
458 * Number of authoritative answers in the packet, should be 0 for queries.
460 unsigned int num_authority_records;
463 * Number of additional records in the packet, should be 0 for queries.
465 unsigned int num_additional_records;
468 * Bitfield of DNS flags.
470 struct GNUNET_DNSPARSER_Flags flags;
473 * DNS ID (to match replies to requests).
481 * Parse a UDP payload of a DNS packet in to a nice struct for further
482 * processing and manipulation.
484 * @param udp_payload wire-format of the DNS packet
485 * @param udp_payload_length number of bytes in udp_payload
486 * @return NULL on error, otherwise the parsed packet
488 struct GNUNET_DNSPARSER_Packet *
489 GNUNET_DNSPARSER_parse (const char *udp_payload,
490 size_t udp_payload_length);
494 * Free memory taken by a packet.
496 * @param p packet to free
499 GNUNET_DNSPARSER_free_packet (struct GNUNET_DNSPARSER_Packet *p);
503 * Given a DNS packet, generate the corresponding UDP payload.
505 * @param p packet to pack
506 * @param max maximum allowed size for the resulting UDP payload
507 * @param buf set to a buffer with the packed message
508 * @param buf_length set to the length of buf
509 * @return GNUNET_SYSERR if 'p' is invalid
510 * GNUNET_NO if 'p' was truncated (but there is still a result in 'buf')
511 * GNUNET_OK if 'p' was packed completely into '*buf'
514 GNUNET_DNSPARSER_pack (const struct GNUNET_DNSPARSER_Packet *p,