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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 * Preference for this entry (lower value is higher preference).
194 * Without the underscore (!). Note that RFC 6335 clarifies the
195 * set of legal characters for service names.
200 * Transport protocol (typcially "tcp" or "udp", but others might be allowed).
201 * Without the underscore (!).
206 * Domain name for which the record is valid
211 * Hostname offering the service.
216 * Preference for this entry (lower value is higher preference). Clients
217 * will contact hosts from the lowest-priority group first and fall back
218 * to higher priorities if the low-priority entries are unavailable.
223 * Relative weight for records with the same priority. Clients will use
224 * the hosts of the same (lowest) priority with a probability proportional
225 * to the weight given.
230 * TCP or UDP port of the service.
238 * Information from SOA records (RFC 1035).
240 struct GNUNET_DNSPARSER_SoaRecord
244 *The domainname of the name server that was the
245 * original or primary source of data for this zone.
250 * A domainname which specifies the mailbox of the
251 * person responsible for this zone.
256 * The version number of the original copy of the zone.
261 * Time interval before the zone should be refreshed.
266 * Time interval that should elapse before a failed refresh should
272 * Time value that specifies the upper limit on the time interval
273 * that can elapse before the zone is no longer authoritative.
278 * The bit minimum TTL field that should be exported with any RR
281 uint32_t minimum_ttl;
287 * Binary record information (unparsed).
289 struct GNUNET_DNSPARSER_RawRecord
293 * Binary record data.
298 * Number of bytes in data.
305 * A DNS response record.
307 struct GNUNET_DNSPARSER_Record
311 * Name of the record that the query is for (0-terminated).
316 * Payload of the record (which one of these is valid depends on the 'type').
322 * For NS, CNAME and PTR records, this is the uncompressed 0-terminated hostname.
327 * SOA data for SOA records.
329 struct GNUNET_DNSPARSER_SoaRecord *soa;
332 * MX data for MX records.
334 struct GNUNET_DNSPARSER_MxRecord *mx;
337 * SRV data for SRV records.
339 struct GNUNET_DNSPARSER_SrvRecord *srv;
342 * Raw data for all other types.
344 struct GNUNET_DNSPARSER_RawRecord raw;
350 * When does the record expire?
352 struct GNUNET_TIME_Absolute expiration_time;
355 * See GNUNET_DNSPARSER_TYPE_*.
360 * See GNUNET_DNSPARSER_CLASS_*.
368 * Easy-to-process, parsed version of a DNS packet.
370 struct GNUNET_DNSPARSER_Packet
373 * Array of all queries in the packet, must contain "num_queries" entries.
375 struct GNUNET_DNSPARSER_Query *queries;
378 * Array of all answers in the packet, must contain "num_answers" entries.
380 struct GNUNET_DNSPARSER_Record *answers;
383 * Array of all authority records in the packet, must contain "num_authority_records" entries.
385 struct GNUNET_DNSPARSER_Record *authority_records;
388 * Array of all additional answers in the packet, must contain "num_additional_records" entries.
390 struct GNUNET_DNSPARSER_Record *additional_records;
393 * Number of queries in the packet.
395 unsigned int num_queries;
398 * Number of answers in the packet, should be 0 for queries.
400 unsigned int num_answers;
403 * Number of authoritative answers in the packet, should be 0 for queries.
405 unsigned int num_authority_records;
408 * Number of additional records in the packet, should be 0 for queries.
410 unsigned int num_additional_records;
413 * Bitfield of DNS flags.
415 struct GNUNET_DNSPARSER_Flags flags;
418 * DNS ID (to match replies to requests).
426 * Parse a UDP payload of a DNS packet in to a nice struct for further
427 * processing and manipulation.
429 * @param udp_payload wire-format of the DNS packet
430 * @param udp_payload_length number of bytes in udp_payload
431 * @return NULL on error, otherwise the parsed packet
433 struct GNUNET_DNSPARSER_Packet *
434 GNUNET_DNSPARSER_parse (const char *udp_payload,
435 size_t udp_payload_length);
439 * Free memory taken by a packet.
441 * @param p packet to free
444 GNUNET_DNSPARSER_free_packet (struct GNUNET_DNSPARSER_Packet *p);
448 * Given a DNS packet, generate the corresponding UDP payload.
450 * @param p packet to pack
451 * @param max maximum allowed size for the resulting UDP payload
452 * @param buf set to a buffer with the packed message
453 * @param buf_length set to the length of buf
454 * @return GNUNET_SYSERR if 'p' is invalid
455 * GNUNET_NO if 'p' was truncated (but there is still a result in 'buf')
456 * GNUNET_OK if 'p' was packed completely into '*buf'
459 GNUNET_DNSPARSER_pack (const struct GNUNET_DNSPARSER_Packet *p,