/* 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; } GNUNET_GCC_STRUCT_LAYOUT; /** * 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