/*
This file is part of GNUnet
- (C) 2010, 2011, 2012 Christian Grothoff (and other contributing authors)
+ (C) 2010-2014 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
+ by the Free Software Foundation; either version 3, or (at your
option) any later version.
GNUnet is distributed in the hope that it will be useful, but
/**
* @file include/gnunet_dnsparser_lib.h
- * @brief API for helper library to parse DNS packets.
+ * @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"
+#include "gnunet_util_lib.h"
+#include "gnunet_tun_lib.h"
/**
* Maximum length of a label in DNS.
#define GNUNET_DNSPARSER_TYPE_TXT 16
#define GNUNET_DNSPARSER_TYPE_AAAA 28
#define GNUNET_DNSPARSER_TYPE_SRV 33
+#define GNUNET_DNSPARSER_TYPE_CERT 37
#define GNUNET_DNSPARSER_TYPE_TLSA 52
+
/**
- * 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).
+ * A DNS query.
*/
-#define GNUNET_DNSPARSER_CLASS_INTERNET 1
-#define GNUNET_DNSPARSER_CLASS_CHAOS 3
-#define GNUNET_DNSPARSER_CLASS_HESIOD 4
+struct GNUNET_DNSPARSER_Query
+{
-#define GNUNET_DNSPARSER_OPCODE_QUERY 0
-#define GNUNET_DNSPARSER_OPCODE_INVERSE_QUERY 1
-#define GNUNET_DNSPARSER_OPCODE_STATUS 2
+ /**
+ * Name of the record that the query is for (0-terminated).
+ * In UTF-8 format. The library will convert from and to DNS-IDNA
+ * as necessary. Use #GNUNET_DNSPARSER_check_label() to test if an
+ * individual label is well-formed. If a given name is not well-formed,
+ * creating the DNS packet will fail.
+ */
+ char *name;
-/**
- * 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
+ /**
+ * See GNUNET_DNSPARSER_TYPE_*.
+ */
+ uint16_t type;
+
+ /**
+ * See GNUNET_TUN_DNS_CLASS_*.
+ */
+ uint16_t dns_traffic_class;
+
+};
-/**
- * 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).
+ * Information from MX records (RFC 1035).
*/
-struct GNUNET_DNSPARSER_Flags
+struct GNUNET_DNSPARSER_MxRecord
{
-#if __BYTE_ORDER == __LITTLE_ENDIAN
+
/**
- * Set to 1 if recursion is desired (client -> server)
+ * Preference for this entry (lower value is higher preference).
*/
- unsigned int recursion_desired : 1 GNUNET_PACKED;
-
+ uint16_t preference;
+
/**
- * Set to 1 if message is truncated
+ * Name of the mail server.
+ * In UTF-8 format. The library will convert from and to DNS-IDNA
+ * as necessary. Use #GNUNET_DNSPARSER_check_label() to test if an
+ * individual label is well-formed. If a given name is not well-formed,
+ * creating the DNS packet will fail.
*/
- unsigned int message_truncated : 1 GNUNET_PACKED;
-
+ char *mxhost;
+
+};
+
+
+/**
+ * Information from SRV records (RFC 2782).
+ */
+struct GNUNET_DNSPARSER_SrvRecord
+{
+
/**
- * Set to 1 if this is an authoritative answer
+ * Hostname offering the service.
+ * In UTF-8 format. The library will convert from and to DNS-IDNA
+ * as necessary. Use #GNUNET_DNSPARSER_check_label() to test if an
+ * individual label is well-formed. If a given name is not well-formed,
+ * creating the DNS packet will fail.
*/
- unsigned int authoritative_answer : 1 GNUNET_PACKED;
-
+ char *target;
+
/**
- * See GNUNET_DNSPARSER_OPCODE_ defines.
+ * Preference for this entry (lower value is higher preference). Clients
+ * will contact hosts from the lowest-priority group first and fall back
+ * to higher priorities if the low-priority entries are unavailable.
*/
- unsigned int opcode : 4 GNUNET_PACKED;
-
+ uint16_t priority;
+
/**
- * query:0, response:1
+ * Relative weight for records with the same priority. Clients will use
+ * the hosts of the same (lowest) priority with a probability proportional
+ * to the weight given.
*/
- unsigned int query_or_response : 1 GNUNET_PACKED;
-
+ uint16_t weight;
+
/**
- * See GNUNET_DNSPARSER_RETURN_CODE_ defines.
+ * TCP or UDP port of the service.
*/
- unsigned int return_code : 4 GNUNET_PACKED;
-
+ uint16_t port;
+
+};
+
+
+/**
+ * DNS CERT types as defined in RFC 4398.
+ */
+enum GNUNET_DNSPARSER_CertType
+{
/**
- * See RFC 4035.
+ * Reserved value
*/
- unsigned int checking_disabled : 1 GNUNET_PACKED;
-
+ GNUNET_DNSPARSER_CERTTYPE_RESERVED = 0,
+
/**
- * Response has been cryptographically verified, RFC 4035.
+ * An x509 PKIX certificate
*/
- unsigned int authenticated_data : 1 GNUNET_PACKED;
-
+ GNUNET_DNSPARSER_CERTTYPE_PKIX = 1,
+
/**
- * Always zero.
+ * A SKPI certificate
*/
- unsigned int zero : 1 GNUNET_PACKED;
-
+ GNUNET_DNSPARSER_CERTTYPE_SKPI = 2,
+
/**
- * Set to 1 if recursion is available (server -> client)
+ * A PGP certificate
*/
- unsigned int recursion_available : 1 GNUNET_PACKED;
-#elif __BYTE_ORDER == __BIG_ENDIAN
-
+ GNUNET_DNSPARSER_CERTTYPE_PGP = 3,
+
/**
- * query:0, response:1
+ * An x509 PKIX cert URL
*/
- unsigned int query_or_response : 1 GNUNET_PACKED;
-
+ GNUNET_DNSPARSER_CERTTYPE_IPKIX = 4,
+
/**
- * See GNUNET_DNSPARSER_OPCODE_ defines.
+ * A SKPI cert URL
*/
- unsigned int opcode : 4 GNUNET_PACKED;
-
+ GNUNET_DNSPARSER_CERTTYPE_ISKPI = 5,
+
/**
- * Set to 1 if this is an authoritative answer
+ * A PGP cert fingerprint and URL
*/
- unsigned int authoritative_answer : 1 GNUNET_PACKED;
-
+ GNUNET_DNSPARSER_CERTTYPE_IPGP = 6,
+
/**
- * Set to 1 if message is truncated
+ * An attribute Certificate
*/
- unsigned int message_truncated : 1 GNUNET_PACKED;
-
+ GNUNET_DNSPARSER_CERTTYPE_ACPKIX = 7,
+
/**
- * Set to 1 if recursion is desired (client -> server)
+ * An attribute cert URL
*/
- unsigned int recursion_desired : 1 GNUNET_PACKED;
+ GNUNET_DNSPARSER_CERTTYPE_IACKPIX = 8
+};
-
+
+/**
+ * DNSCERT algorithms as defined in http://www.iana.org/assignments/
+ * dns-sec-alg-numbers/dns-sec-alg-numbers.xhtml, under dns-sec-alg-numbers-1
+ */
+enum GNUNET_DNSPARSER_CertAlgorithm
+{
/**
- * Set to 1 if recursion is available (server -> client)
+ * No defined
*/
- unsigned int recursion_available : 1 GNUNET_PACKED;
-
+ GNUNET_DNSPARSER_CERTALGO_UNDEFINED = 0,
+
/**
- * Always zero.
+ * RSA/MD5
*/
- unsigned int zero : 1 GNUNET_PACKED;
-
+ GNUNET_DNSPARSER_CERTALGO_RSAMD5 = 1,
+
/**
- * Response has been cryptographically verified, RFC 4035.
+ * Diffie-Hellman
*/
- unsigned int authenticated_data : 1 GNUNET_PACKED;
-
+ GNUNET_DNSPARSER_CERTALGO_DH = 2,
+
/**
- * See RFC 4035.
+ * DSA/SHA1
*/
- unsigned int checking_disabled : 1 GNUNET_PACKED;
-
+ GNUNET_DNSPARSER_CERTALGO_DSASHA = 3,
+
/**
- * See GNUNET_DNSPARSER_RETURN_CODE_ defines.
- */
- unsigned int return_code : 4 GNUNET_PACKED;
-#else
- #error byteorder undefined
-#endif
-
-} GNUNET_GCC_STRUCT_LAYOUT;
+ * Reserved
+ */
+ GNUNET_DNSPARSER_CERTALGO_RSRVD4 = 4,
+ /**
+ * RSA/SHA1
+ */
+ GNUNET_DNSPARSER_CERTALGO_RSASHA = 5,
-/**
- * A DNS query.
- */
-struct GNUNET_DNSPARSER_Query
-{
+ /**
+ * DSA/NSEC3/SHA
+ */
+ GNUNET_DNSPARSER_CERTALGO_DSANSEC3 = 6,
/**
- * Name of the record that the query is for (0-terminated).
- * In UTF-8 format. The library will convert from and to DNS-IDNA
- * as necessary. Use 'GNUNET_DNSPARSER_check_label' to test if an
- * individual label is well-formed. If a given name is not well-formed,
- * creating the DNS packet will fail.
+ * RSA/NSEC3/SHA
*/
- char *name;
+ GNUNET_DNSPARSER_CERTALGO_RSANSEC3 = 7,
/**
- * See GNUNET_DNSPARSER_TYPE_*.
+ * RSA/SHA256
*/
- uint16_t type;
+ GNUNET_DNSPARSER_CERTALGO_RSASHA256 = 8,
/**
- * See GNUNET_DNSPARSER_CLASS_*.
+ * Reserved
*/
- uint16_t class;
+ GNUNET_DNSPARSER_CERTALGO_RSRVD9 = 9,
-};
+ /**
+ * RSA/SHA512
+ */
+ GNUNET_DNSPARSER_CERTALGO_RSASHA512 = 10,
+ /**
+ * GOST R 34.10-2001
+ */
+ GNUNET_DNSPARSER_CERTALGO_GOST_R34 = 12,
-/**
- * Information from MX records (RFC 1035).
- */
-struct GNUNET_DNSPARSER_MxRecord
-{
-
/**
- * Preference for this entry (lower value is higher preference).
+ * ECDSA Curve P-256/SHA256
*/
- uint16_t preference;
+ GNUNET_DNSPARSER_CERTALGO_ECDSA_P256SHA256 = 13,
/**
- * Name of the mail server.
- * In UTF-8 format. The library will convert from and to DNS-IDNA
- * as necessary. Use 'GNUNET_DNSPARSER_check_label' to test if an
- * individual label is well-formed. If a given name is not well-formed,
- * creating the DNS packet will fail.
+ * ECDSA Curve P-384/SHA384
*/
- char *mxhost;
+ GNUNET_DNSPARSER_CERTALGO_ECDSA_P384SHA384 = 14
};
/**
- * Information from SRV records (RFC 2782). The 'service', 'proto'
- * and 'domain_name' fields together give the DNS-name which for SRV
- * records is of the form "_$SERVICE._$PROTO.$DOMAIN_NAME". The DNS
- * parser provides the full name in 'struct DNSPARSER_Record' and the
- * individual components in the respective fields of this struct.
- * When serializing, you CAN set the 'name' field of 'struct
- * GNUNET_DNSPARSER_Record' to NULL, in which case the DNSPARSER code
- * will populate 'name' from the 'service', 'proto' and 'domain_name'
- * fields in this struct.
+ * Information from CERT records (RFC 4034).
*/
-struct GNUNET_DNSPARSER_SrvRecord
+struct GNUNET_DNSPARSER_CertRecord
{
-
- /**
- * Service name without the underscore (!). Note that RFC 6335 clarifies the
- * set of legal characters for service names.
- * In UTF-8 format. The library will convert from and to DNS-IDNA
- * as necessary. Use 'GNUNET_DNSPARSER_check_label' to test if an
- * individual label is well-formed. If a given name is not well-formed,
- * creating the DNS packet will fail.
- */
- char *service;
-
- /**
- * Transport protocol (typcially "tcp" or "udp", but others might be allowed).
- * Without the underscore (!).
- */
- char *proto;
/**
- * Domain name for which the record is valid
- * In UTF-8 format. The library will convert from and to DNS-IDNA
- * as necessary. Use 'GNUNET_DNSPARSER_check_label' to test if an
- * individual label is well-formed. If a given name is not well-formed,
- * creating the DNS packet will fail.
+ * Certificate type
*/
- char *domain_name;
+ enum GNUNET_DNSPARSER_CertType cert_type;
/**
- * Hostname offering the service.
- * In UTF-8 format. The library will convert from and to DNS-IDNA
- * as necessary. Use 'GNUNET_DNSPARSER_check_label' to test if an
- * individual label is well-formed. If a given name is not well-formed,
- * creating the DNS packet will fail.
+ * Certificate KeyTag
*/
- char *target;
+ uint16_t cert_tag;
/**
- * Preference for this entry (lower value is higher preference). Clients
- * will contact hosts from the lowest-priority group first and fall back
- * to higher priorities if the low-priority entries are unavailable.
+ * Algorithm
*/
- uint16_t priority;
+ enum GNUNET_DNSPARSER_CertAlgorithm algorithm;
/**
- * Relative weight for records with the same priority. Clients will use
- * the hosts of the same (lowest) priority with a probability proportional
- * to the weight given.
+ * Number of bytes in @e certificate_data
*/
- uint16_t weight;
+ size_t certificate_size;
/**
- * TCP or UDP port of the service.
+ * Data of the certificate.
*/
- uint16_t port;
+ char *certificate_data;
};
-
+
/**
* Information from SOA records (RFC 1035).
*/
struct GNUNET_DNSPARSER_SoaRecord
{
-
+
/**
- *The domainname of the name server that was the
+ * The domainname of the name server that was the
* original or primary source of data for this zone.
- * In UTF-8 format. The library will convert from and to DNS-IDNA
- * as necessary. Use 'GNUNET_DNSPARSER_check_label' to test if an
+ * In UTF-8 format. The library will convert from and to DNS-IDNA
+ * as necessary. Use #GNUNET_DNSPARSER_check_label() to test if an
* individual label is well-formed. If a given name is not well-formed,
* creating the DNS packet will fail.
*/
/**
* A domainname which specifies the mailbox of the
* person responsible for this zone.
- * In UTF-8 format. The library will convert from and to DNS-IDNA
- * as necessary. Use 'GNUNET_DNSPARSER_check_label' to test if an
+ * In UTF-8 format. The library will convert from and to DNS-IDNA
+ * as necessary. Use #GNUNET_DNSPARSER_check_label() to test if an
* individual label is well-formed. If a given name is not well-formed,
* creating the DNS packet will fail.
*/
char *rname;
/**
- * The version number of the original copy of the zone.
+ * The version number of the original copy of the zone.
*/
uint32_t serial;
* from this zone.
*/
uint32_t minimum_ttl;
-
+
};
/**
* Name of the record that the query is for (0-terminated).
- * In UTF-8 format. The library will convert from and to DNS-IDNA
- * as necessary. Use 'GNUNET_DNSPARSER_check_label' to test if an
+ * In UTF-8 format. The library will convert from and to DNS-IDNA
+ * as necessary. Use #GNUNET_DNSPARSER_check_label() to test if an
* individual label is well-formed. If a given name is not well-formed,
* creating the DNS packet will fail.
*/
/**
* Payload of the record (which one of these is valid depends on the 'type').
*/
- union
+ union
{
/**
* For NS, CNAME and PTR records, this is the uncompressed 0-terminated hostname.
- * In UTF-8 format. The library will convert from and to DNS-IDNA
- * as necessary. Use 'GNUNET_DNSPARSER_check_label' to test if an
+ * In UTF-8 format. The library will convert from and to DNS-IDNA
+ * as necessary. Use #GNUNET_DNSPARSER_check_label() to test if an
* individual label is well-formed. If a given name is not well-formed,
* creating the DNS packet will fail.
*/
char *hostname;
-
+
/**
* SOA data for SOA records.
*/
struct GNUNET_DNSPARSER_SoaRecord *soa;
-
+
+ /**
+ * CERT data for CERT records.
+ */
+ struct GNUNET_DNSPARSER_CertRecord *cert;
+
/**
* MX data for MX records.
*/
uint16_t type;
/**
- * See GNUNET_DNSPARSER_CLASS_*.
+ * See GNUNET_TUN_DNS_CLASS_*.
*/
- uint16_t class;
+ uint16_t dns_traffic_class;
};
/**
* Bitfield of DNS flags.
- */
- struct GNUNET_DNSPARSER_Flags flags;
+ */
+ struct GNUNET_TUN_DnsFlags flags;
/**
* DNS ID (to match replies to requests).
* This can fail if the ASCII-conversion becomes longer than 63 characters.
*
* @param label label to check (UTF-8 string)
- * @return GNUNET_OK if the label can be converted to IDNA,
- * GNUNET_SYSERR if the label is not valid for DNS names
+ * @return #GNUNET_OK if the label can be converted to IDNA,
+ * #GNUNET_SYSERR if the label is not valid for DNS names
*/
int
GNUNET_DNSPARSER_check_label (const char *label);
* the entire name exceeds 253 characters.
*
* @param name name to check (UTF-8 string)
- * @return GNUNET_OK if the label can be converted to IDNA,
- * GNUNET_SYSERR if the label is not valid for DNS names
+ * @return #GNUNET_OK if the label can be converted to IDNA,
+ * #GNUNET_SYSERR if the label is not valid for DNS names
*/
int
GNUNET_DNSPARSER_check_name (const char *name);
* processing and manipulation.
*
* @param udp_payload wire-format of the DNS packet
- * @param udp_payload_length number of bytes in udp_payload
+ * @param udp_payload_length number of bytes in @a udp_payload
* @return NULL on error, otherwise the parsed packet
*/
struct GNUNET_DNSPARSER_Packet *
/**
- * Given a DNS packet, generate the corresponding UDP payload.
+ * Given a DNS packet @a p, generate the corresponding UDP payload.
+ * Note that we do not attempt to pack the strings with pointers
+ * as this would complicate the code and this is about being
+ * simple and secure, not fast, fancy and broken like bind.
*
* @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'
+ * @param buf_length set to the length of @a buf
+ * @return #GNUNET_SYSERR if @a p is invalid
+ * #GNUNET_NO if @a p was truncated (but there is still a result in @a buf)
+ * #GNUNET_OK if @a p was packed completely into @a buf
*/
int
GNUNET_DNSPARSER_pack (const struct GNUNET_DNSPARSER_Packet *p,
char **buf,
size_t *buf_length);
+/* ***************** low-level packing API ******************** */
+
+/**
+ * Add a DNS name to the UDP packet at the given location, converting
+ * the name to IDNA notation as necessary.
+ *
+ * @param dst where to write the name (UDP packet)
+ * @param dst_len number of bytes in @a dst
+ * @param off pointer to offset where to write the name (increment by bytes used)
+ * must not be changed if there is an error
+ * @param name name to write
+ * @return #GNUNET_SYSERR if @a name is invalid
+ * #GNUNET_NO if @a name did not fit
+ * #GNUNET_OK if @a name was added to @a dst
+ */
+int
+GNUNET_DNSPARSER_builder_add_name (char *dst,
+ size_t dst_len,
+ size_t *off,
+ const char *name);
+
+
+/**
+ * Add a DNS query to the UDP packet at the given location.
+ *
+ * @param dst where to write the query
+ * @param dst_len number of bytes in @a dst
+ * @param off pointer to offset where to write the query (increment by bytes used)
+ * must not be changed if there is an error
+ * @param query query to write
+ * @return #GNUNET_SYSERR if @a query is invalid
+ * #GNUNET_NO if @a query did not fit
+ * #GNUNET_OK if @a query was added to @a dst
+ */
+int
+GNUNET_DNSPARSER_builder_add_query (char *dst,
+ size_t dst_len,
+ size_t *off,
+ const struct GNUNET_DNSPARSER_Query *query);
+
+
+/**
+ * Add an MX record to the UDP packet at the given location.
+ *
+ * @param dst where to write the mx record
+ * @param dst_len number of bytes in @a dst
+ * @param off pointer to offset where to write the mx information (increment by bytes used);
+ * can also change if there was an error
+ * @param mx mx information to write
+ * @return #GNUNET_SYSERR if @a mx is invalid
+ * #GNUNET_NO if @a mx did not fit
+ * #GNUNET_OK if @a mx was added to @a dst
+ */
+int
+GNUNET_DNSPARSER_builder_add_mx (char *dst,
+ size_t dst_len,
+ size_t *off,
+ const struct GNUNET_DNSPARSER_MxRecord *mx);
+
+
+/**
+ * Add an SOA record to the UDP packet at the given location.
+ *
+ * @param dst where to write the SOA record
+ * @param dst_len number of bytes in @a dst
+ * @param off pointer to offset where to write the SOA information (increment by bytes used)
+ * can also change if there was an error
+ * @param soa SOA information to write
+ * @return #GNUNET_SYSERR if @a soa is invalid
+ * #GNUNET_NO if @a soa did not fit
+ * #GNUNET_OK if @a soa was added to @a dst
+ */
+int
+GNUNET_DNSPARSER_builder_add_soa (char *dst,
+ size_t dst_len,
+ size_t *off,
+ const struct GNUNET_DNSPARSER_SoaRecord *soa);
+
+
+/**
+ * Add CERT record to the UDP packet at the given location.
+ *
+ * @param dst where to write the CERT record
+ * @param dst_len number of bytes in @a dst
+ * @param off pointer to offset where to write the CERT information (increment by bytes used)
+ * can also change if there was an error
+ * @param cert CERT information to write
+ * @return #GNUNET_SYSERR if @a soa is invalid
+ * #GNUNET_NO if @a soa did not fit
+ * #GNUNET_OK if @a soa was added to @a dst
+ */
+int
+GNUNET_DNSPARSER_builder_add_cert (char *dst,
+ size_t dst_len,
+ size_t *off,
+ const struct GNUNET_DNSPARSER_CertRecord *cert);
+
+
+/**
+ * Add an SRV record to the UDP packet at the given location.
+ *
+ * @param dst where to write the SRV record
+ * @param dst_len number of bytes in @a dst
+ * @param off pointer to offset where to write the SRV information (increment by bytes used)
+ * can also change if there was an error
+ * @param srv SRV information to write
+ * @return #GNUNET_SYSERR if @a srv is invalid
+ * #GNUNET_NO if @a srv did not fit
+ * #GNUNET_OK if @a srv was added to @a dst
+ */
+int
+GNUNET_DNSPARSER_builder_add_srv (char *dst,
+ size_t dst_len,
+ size_t *off,
+ const struct GNUNET_DNSPARSER_SrvRecord *srv);
+
+/* ***************** low-level parsing API ******************** */
+
+/**
+ * Parse a DNS record entry.
+ *
+ * @param udp_payload entire UDP payload
+ * @param udp_payload_length length of @a udp_payload
+ * @param off pointer to the offset of the record to parse in the udp_payload (to be
+ * incremented by the size of the record)
+ * @param r where to write the record information
+ * @return #GNUNET_OK on success, #GNUNET_SYSERR if the record is malformed
+ */
+int
+GNUNET_DNSPARSER_parse_record (const char *udp_payload,
+ size_t udp_payload_length,
+ size_t *off,
+ struct GNUNET_DNSPARSER_Record *r);
+
+
+/**
+ * Parse name inside of a DNS query or record.
+ *
+ * @param udp_payload entire UDP payload
+ * @param udp_payload_length length of @a udp_payload
+ * @param off pointer to the offset of the name to parse in the udp_payload (to be
+ * incremented by the size of the name)
+ * @return name as 0-terminated C string on success, NULL if the payload is malformed
+ */
+char *
+GNUNET_DNSPARSER_parse_name (const char *udp_payload,
+ size_t udp_payload_length,
+ size_t *off);
+
+
+/**
+ * Parse a DNS query entry.
+ *
+ * @param udp_payload entire UDP payload
+ * @param udp_payload_length length of @a udp_payload
+ * @param off pointer to the offset of the query to parse in the udp_payload (to be
+ * incremented by the size of the query)
+ * @param q where to write the query information
+ * @return #GNUNET_OK on success, #GNUNET_SYSERR if the query is malformed
+ */
+int
+GNUNET_DNSPARSER_parse_query (const char *udp_payload,
+ size_t udp_payload_length,
+ size_t *off,
+ struct GNUNET_DNSPARSER_Query *q);
+
+
+/**
+ * Parse a DNS SOA record.
+ *
+ * @param udp_payload reference to UDP packet
+ * @param udp_payload_length length of @a udp_payload
+ * @param off pointer to the offset of the query to parse in the SOA record (to be
+ * incremented by the size of the record), unchanged on error
+ * @return the parsed SOA record, NULL on error
+ */
+struct GNUNET_DNSPARSER_SoaRecord *
+GNUNET_DNSPARSER_parse_soa (const char *udp_payload,
+ size_t udp_payload_length,
+ size_t *off);
+
+
+/**
+ * Parse a DNS CERT record.
+ *
+ * @param udp_payload reference to UDP packet
+ * @param udp_payload_length length of @a udp_payload
+ * @param off pointer to the offset of the query to parse in the CERT record (to be
+ * incremented by the size of the record), unchanged on error
+ * @return the parsed CERT record, NULL on error
+ */
+struct GNUNET_DNSPARSER_CertRecord *
+GNUNET_DNSPARSER_parse_cert (const char *udp_payload,
+ size_t udp_payload_length,
+ size_t *off);
+
+
+/**
+ * Parse a DNS MX record.
+ *
+ * @param udp_payload reference to UDP packet
+ * @param udp_payload_length length of @a udp_payload
+ * @param off pointer to the offset of the query to parse in the MX record (to be
+ * incremented by the size of the record), unchanged on error
+ * @return the parsed MX record, NULL on error
+ */
+struct GNUNET_DNSPARSER_MxRecord *
+GNUNET_DNSPARSER_parse_mx (const char *udp_payload,
+ size_t udp_payload_length,
+ size_t *off);
+
+
+/**
+ * Parse a DNS SRV record.
+ *
+ * @param udp_payload reference to UDP packet
+ * @param udp_payload_length length of @a udp_payload
+ * @param off pointer to the offset of the query to parse in the SRV record (to be
+ * incremented by the size of the record), unchanged on error
+ * @return the parsed SRV record, NULL on error
+ */
+struct GNUNET_DNSPARSER_SrvRecord *
+GNUNET_DNSPARSER_parse_srv (const char *udp_payload,
+ size_t udp_payload_length,
+ size_t *off);
+
+/* ***************** low-level deallocation API ******************** */
+
+/**
+ * Free the given DNS record.
+ *
+ * @param r record to free
+ */
+void
+GNUNET_DNSPARSER_free_record (struct GNUNET_DNSPARSER_Record *r);
+
+
+/**
+ * Free MX information record.
+ *
+ * @param mx record to free
+ */
+void
+GNUNET_DNSPARSER_free_mx (struct GNUNET_DNSPARSER_MxRecord *mx);
+
+
+/**
+ * Free SRV information record.
+ *
+ * @param srv record to free
+ */
+void
+GNUNET_DNSPARSER_free_srv (struct GNUNET_DNSPARSER_SrvRecord *srv);
+
+
+/**
+ * Free SOA information record.
+ *
+ * @param soa record to free
+ */
+void
+GNUNET_DNSPARSER_free_soa (struct GNUNET_DNSPARSER_SoaRecord *soa);
+
+
+/**
+ * Free CERT information record.
+ *
+ * @param cert record to free
+ */
+void
+GNUNET_DNSPARSER_free_cert (struct GNUNET_DNSPARSER_CertRecord *cert);
+
+
+/**
+ * Convert a block of binary data to HEX.
+ *
+ * @param data binary data to convert
+ * @param data_size number of bytes in @a data
+ * @return HEX string (lower case)
+ */
+char *
+GNUNET_DNSPARSER_bin_to_hex (const void *data,
+ size_t data_size);
+
+
+/**
+ * Convert a HEX string to block of binary data.
+ *
+ * @param hex HEX string to convert (may contain mixed case)
+ * @param data where to write result, must be
+ * at least `strlen(hex)/2` bytes long
+ * @return number of bytes written to data
+ */
+size_t
+GNUNET_DNSPARSER_hex_to_bin (const char *hex,
+ void *data);
+
#endif