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Diffstat (limited to 'src/include/gnunet_dnsparser_lib.h')
| -rw-r--r-- | src/include/gnunet_dnsparser_lib.h | 397 |
1 files changed, 397 insertions, 0 deletions
diff --git a/src/include/gnunet_dnsparser_lib.h b/src/include/gnunet_dnsparser_lib.h new file mode 100644 index 0000000..0c310ba --- /dev/null +++ b/src/include/gnunet_dnsparser_lib.h @@ -0,0 +1,397 @@ +/* + This file is part of GNUnet + (C) 2010, 2011, 2012 Christian Grothoff (and other contributing authors) + + GNUnet is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published + by the Free Software Foundation; either version 2, or (at your + option) any later version. + + GNUnet is distributed in the hope that it will be useful, but + WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + General Public License for more details. + + You should have received a copy of the GNU General Public License + along with GNUnet; see the file COPYING. If not, write to the + Free Software Foundation, Inc., 59 Temple Place - Suite 330, + Boston, MA 02111-1307, USA. + */ + +/** + * @file include/gnunet_dnsparser_lib.h + * @brief API for helper library to parse DNS packets. + * @author Philipp Toelke + * @author Christian Grothoff + */ +#ifndef GNUNET_DNSPARSER_LIB_H +#define GNUNET_DNSPARSER_LIB_H + +#include "platform.h" +#include "gnunet_common.h" + +/** + * A few common DNS types. + */ +#define GNUNET_DNSPARSER_TYPE_A 1 +#define GNUNET_DNSPARSER_TYPE_NS 2 +#define GNUNET_DNSPARSER_TYPE_CNAME 5 +#define GNUNET_DNSPARSER_TYPE_SOA 6 +#define GNUNET_DNSPARSER_TYPE_PTR 12 +#define GNUNET_DNSPARSER_TYPE_MX 15 +#define GNUNET_DNSPARSER_TYPE_TXT 16 +#define GNUNET_DNSPARSER_TYPE_AAAA 28 + +/** + * A few common DNS classes (ok, only one is common, but I list a + * couple more to make it clear what we're talking about here). + */ +#define GNUNET_DNSPARSER_CLASS_INTERNET 1 +#define GNUNET_DNSPARSER_CLASS_CHAOS 3 +#define GNUNET_DNSPARSER_CLASS_HESIOD 4 + +#define GNUNET_DNSPARSER_OPCODE_QUERY 0 +#define GNUNET_DNSPARSER_OPCODE_INVERSE_QUERY 1 +#define GNUNET_DNSPARSER_OPCODE_STATUS 2 + +/** + * RFC 1035 codes. + */ +#define GNUNET_DNSPARSER_RETURN_CODE_NO_ERROR 0 +#define GNUNET_DNSPARSER_RETURN_CODE_FORMAT_ERROR 1 +#define GNUNET_DNSPARSER_RETURN_CODE_SERVER_FAILURE 2 +#define GNUNET_DNSPARSER_RETURN_CODE_NAME_ERROR 3 +#define GNUNET_DNSPARSER_RETURN_CODE_NOT_IMPLEMENTED 4 +#define GNUNET_DNSPARSER_RETURN_CODE_REFUSED 5 + +/** + * RFC 2136 codes + */ +#define GNUNET_DNSPARSER_RETURN_CODE_YXDOMAIN 6 +#define GNUNET_DNSPARSER_RETURN_CODE_YXRRSET 7 +#define GNUNET_DNSPARSER_RETURN_CODE_NXRRSET 8 +#define GNUNET_DNSPARSER_RETURN_CODE_NOT_AUTH 9 +#define GNUNET_DNSPARSER_RETURN_CODE_NOT_ZONE 10 + +/** + * DNS flags (largely RFC 1035 / RFC 2136). + */ +struct GNUNET_DNSPARSER_Flags +{ + /** + * Set to 1 if recursion is desired (client -> server) + */ + unsigned int recursion_desired : 1 GNUNET_PACKED; + + /** + * Set to 1 if message is truncated + */ + unsigned int message_truncated : 1 GNUNET_PACKED; + + /** + * Set to 1 if this is an authoritative answer + */ + unsigned int authoritative_answer : 1 GNUNET_PACKED; + + /** + * See GNUNET_DNSPARSER_OPCODE_ defines. + */ + unsigned int opcode : 4 GNUNET_PACKED; + + /** + * query:0, response:1 + */ + unsigned int query_or_response : 1 GNUNET_PACKED; + + /** + * See GNUNET_DNSPARSER_RETURN_CODE_ defines. + */ + unsigned int return_code : 4 GNUNET_PACKED; + + /** + * See RFC 4035. + */ + unsigned int checking_disabled : 1 GNUNET_PACKED; + + /** + * Response has been cryptographically verified, RFC 4035. + */ + unsigned int authenticated_data : 1 GNUNET_PACKED; + + /** + * Always zero. + */ + unsigned int zero : 1 GNUNET_PACKED; + + /** + * Set to 1 if recursion is available (server -> client) + */ + unsigned int recursion_available : 1 GNUNET_PACKED; + +}; + + +/** + * A DNS query. + */ +struct GNUNET_DNSPARSER_Query +{ + + /** + * Name of the record that the query is for (0-terminated). + */ + char *name; + + /** + * See GNUNET_DNSPARSER_TYPE_*. + */ + uint16_t type; + + /** + * See GNUNET_DNSPARSER_CLASS_*. + */ + uint16_t class; + +}; + + +/** + * Information from MX records (RFC 1035). + */ +struct GNUNET_DNSPARSER_MxRecord +{ + + /** + * Preference for this entry (lower value is higher preference). + */ + uint16_t preference; + + /** + * Name of the mail server. + */ + char *mxhost; + +}; + + +/** + * Information from SOA records (RFC 1035). + */ +struct GNUNET_DNSPARSER_SoaRecord +{ + + /** + *The domainname of the name server that was the + * original or primary source of data for this zone. + */ + char *mname; + + /** + * A domainname which specifies the mailbox of the + * person responsible for this zone. + */ + char *rname; + + /** + * The version number of the original copy of the zone. + */ + uint32_t serial; + + /** + * Time interval before the zone should be refreshed. + */ + uint32_t refresh; + + /** + * Time interval that should elapse before a failed refresh should + * be retried. + */ + uint32_t retry; + + /** + * Time value that specifies the upper limit on the time interval + * that can elapse before the zone is no longer authoritative. + */ + uint32_t expire; + + /** + * The bit minimum TTL field that should be exported with any RR + * from this zone. + */ + uint32_t minimum_ttl; + +}; + + +/** + * Binary record information (unparsed). + */ +struct GNUNET_DNSPARSER_RawRecord +{ + + /** + * Binary record data. + */ + void *data; + + /** + * Number of bytes in data. + */ + size_t data_len; +}; + + +/** + * A DNS response record. + */ +struct GNUNET_DNSPARSER_Record +{ + + /** + * Name of the record that the query is for (0-terminated). + */ + char *name; + + union + { + + /** + * For NS, CNAME and PTR records, this is the uncompressed 0-terminated hostname. + */ + char *hostname; + + /** + * SOA data for SOA records. + */ + struct GNUNET_DNSPARSER_SoaRecord *soa; + + /** + * MX data for MX records. + */ + struct GNUNET_DNSPARSER_MxRecord *mx; + + /** + * Raw data for all other types. + */ + struct GNUNET_DNSPARSER_RawRecord raw; + + } data; + + + /** + * When does the record expire? + */ + struct GNUNET_TIME_Absolute expiration_time; + + /** + * See GNUNET_DNSPARSER_TYPE_*. + */ + uint16_t type; + + /** + * See GNUNET_DNSPARSER_CLASS_*. + */ + uint16_t class; + +}; + + +/** + * Easy-to-process, parsed version of a DNS packet. + */ +struct GNUNET_DNSPARSER_Packet +{ + /** + * Array of all queries in the packet, must contain "num_queries" entries. + */ + struct GNUNET_DNSPARSER_Query *queries; + + /** + * Array of all answers in the packet, must contain "num_answers" entries. + */ + struct GNUNET_DNSPARSER_Record *answers; + + /** + * Array of all authority records in the packet, must contain "num_authority_records" entries. + */ + struct GNUNET_DNSPARSER_Record *authority_records; + + /** + * Array of all additional answers in the packet, must contain "num_additional_records" entries. + */ + struct GNUNET_DNSPARSER_Record *additional_records; + + /** + * Number of queries in the packet. + */ + unsigned int num_queries; + + /** + * Number of answers in the packet, should be 0 for queries. + */ + unsigned int num_answers; + + /** + * Number of authoritative answers in the packet, should be 0 for queries. + */ + unsigned int num_authority_records; + + /** + * Number of additional records in the packet, should be 0 for queries. + */ + unsigned int num_additional_records; + + /** + * Bitfield of DNS flags. + */ + struct GNUNET_DNSPARSER_Flags flags; + + /** + * DNS ID (to match replies to requests). + */ + uint16_t id; + +}; + + +/** + * Parse a UDP payload of a DNS packet in to a nice struct for further + * processing and manipulation. + * + * @param udp_payload wire-format of the DNS packet + * @param udp_payload_length number of bytes in udp_payload + * @return NULL on error, otherwise the parsed packet + */ +struct GNUNET_DNSPARSER_Packet * +GNUNET_DNSPARSER_parse (const char *udp_payload, + size_t udp_payload_length); + + +/** + * Free memory taken by a packet. + * + * @param p packet to free + */ +void +GNUNET_DNSPARSER_free_packet (struct GNUNET_DNSPARSER_Packet *p); + + +/** + * Given a DNS packet, generate the corresponding UDP payload. + * + * @param p packet to pack + * @param max maximum allowed size for the resulting UDP payload + * @param buf set to a buffer with the packed message + * @param buf_length set to the length of buf + * @return GNUNET_SYSERR if 'p' is invalid + * GNUNET_NO if 'p' was truncated (but there is still a result in 'buf') + * GNUNET_OK if 'p' was packed completely into '*buf' + */ +int +GNUNET_DNSPARSER_pack (const struct GNUNET_DNSPARSER_Packet *p, + uint16_t max, + char **buf, + size_t *buf_length); + + +#endif |