A C library for asynchronous DNS requests (grpc依赖)
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/* MIT License
*
* Copyright (c) 2023 Brad House
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice (including the next
* paragraph) shall be included in all copies or substantial portions of the
* Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*
* SPDX-License-Identifier: MIT
*/
#ifndef __ARES_DNS_RECORD_H
#define __ARES_DNS_RECORD_H
/* Include ares.h, not this file directly */
#ifdef __cplusplus
extern "C" {
#endif
/*! \addtogroup ares_dns_record DNS Record Handling
*
* This is a set of functions to create and manipulate DNS records.
*
* @{
*/
/*! DNS Record types handled by c-ares. Some record types may only be valid
* on requests (e.g. ARES_REC_TYPE_ANY), and some may only be valid on
* responses */
typedef enum {
ARES_REC_TYPE_A = 1, /*!< Host address. */
ARES_REC_TYPE_NS = 2, /*!< Authoritative server. */
ARES_REC_TYPE_CNAME = 5, /*!< Canonical name. */
ARES_REC_TYPE_SOA = 6, /*!< Start of authority zone. */
ARES_REC_TYPE_PTR = 12, /*!< Domain name pointer. */
ARES_REC_TYPE_HINFO = 13, /*!< Host information. */
ARES_REC_TYPE_MX = 15, /*!< Mail routing information. */
ARES_REC_TYPE_TXT = 16, /*!< Text strings. */
ARES_REC_TYPE_SIG = 24, /*!< RFC 2535 / RFC 2931. SIG Record */
ARES_REC_TYPE_AAAA = 28, /*!< RFC 3596. Ip6 Address. */
ARES_REC_TYPE_SRV = 33, /*!< RFC 2782. Server Selection. */
ARES_REC_TYPE_NAPTR = 35, /*!< RFC 3403. Naming Authority Pointer */
ARES_REC_TYPE_OPT = 41, /*!< RFC 6891. EDNS0 option (meta-RR) */
ARES_REC_TYPE_TLSA = 52, /*!< RFC 6698. DNS-Based Authentication of Named
* Entities (DANE) Transport Layer Security
* (TLS) Protocol: TLSA */
ARES_REC_TYPE_SVCB = 64, /*!< RFC 9460. General Purpose Service Binding */
ARES_REC_TYPE_HTTPS = 65, /*!< RFC 9460. Service Binding type for use with
* HTTPS */
ARES_REC_TYPE_ANY = 255, /*!< Wildcard match. Not response RR. */
ARES_REC_TYPE_URI = 256, /*!< RFC 7553. Uniform Resource Identifier */
ARES_REC_TYPE_CAA = 257, /*!< RFC 6844. Certification Authority
* Authorization. */
ARES_REC_TYPE_RAW_RR = 65536 /*!< Used as an indicator that the RR record
* is not parsed, but provided in wire
* format */
} ares_dns_rec_type_t;
/*! DNS Classes for requests and responses. */
typedef enum {
ARES_CLASS_IN = 1, /*!< Internet */
ARES_CLASS_CHAOS = 3, /*!< CHAOS */
ARES_CLASS_HESOID = 4, /*!< Hesoid [Dyer 87] */
ARES_CLASS_NONE = 254, /*!< RFC 2136 */
ARES_CLASS_ANY = 255 /*!< Any class (requests only) */
} ares_dns_class_t;
/*! DNS RR Section type */
typedef enum {
ARES_SECTION_ANSWER = 1, /*!< Answer section */
ARES_SECTION_AUTHORITY = 2, /*!< Authority section */
ARES_SECTION_ADDITIONAL = 3 /*!< Additional information section */
} ares_dns_section_t;
/*! DNS Header opcodes */
typedef enum {
ARES_OPCODE_QUERY = 0, /*!< Standard query */
ARES_OPCODE_IQUERY = 1, /*!< Inverse query. Obsolete. */
ARES_OPCODE_STATUS = 2, /*!< Name server status query */
ARES_OPCODE_NOTIFY = 4, /*!< Zone change notification (RFC 1996) */
ARES_OPCODE_UPDATE = 5 /*!< Zone update message (RFC2136) */
} ares_dns_opcode_t;
/*! DNS Header flags */
typedef enum {
ARES_FLAG_QR = 1 << 0, /*!< QR. If set, is a response */
ARES_FLAG_AA = 1 << 1, /*!< Authoritative Answer. If set, is authoritative */
ARES_FLAG_TC = 1 << 2, /*!< Truncation. If set, is truncated response */
ARES_FLAG_RD = 1 << 3, /*!< Recursion Desired. If set, recursion is desired */
ARES_FLAG_RA = 1 << 4, /*!< Recursion Available. If set, server supports
* recursion */
ARES_FLAG_AD = 1 << 5, /*!< RFC 2065. Authentic Data bit indicates in a
* response that the data included has been verified by
* the server providing it */
ARES_FLAG_CD = 1 << 6 /*!< RFC 2065. Checking Disabled bit indicates in a
* query that non-verified data is acceptable to the
* resolver sending the query. */
} ares_dns_flags_t;
/*! DNS Response Codes from server */
typedef enum {
ARES_RCODE_NOERROR = 0, /*!< Success */
ARES_RCODE_FORMERR = 1, /*!< Format error. The name server was unable
* to interpret the query. */
ARES_RCODE_SERVFAIL = 2, /*!< Server Failure. The name server was
* unable to process this query due to a
* problem with the nameserver */
ARES_RCODE_NXDOMAIN = 3, /*!< Name Error. Meaningful only for
* responses from an authoritative name
* server, this code signifies that the
* domain name referenced in the query does
* not exist. */
ARES_RCODE_NOTIMP = 4, /*!< Not implemented. The name server does
* not support the requested kind of
* query */
ARES_RCODE_REFUSED = 5, /*!< Refused. The name server refuses to
* perform the specified operation for
* policy reasons. */
ARES_RCODE_YXDOMAIN = 6, /*!< RFC 2136. Some name that ought not to
* exist, does exist. */
ARES_RCODE_YXRRSET = 7, /*!< RFC 2136. Some RRset that ought to not
* exist, does exist. */
ARES_RCODE_NXRRSET = 8, /*!< RFC 2136. Some RRset that ought to exist,
* does not exist. */
ARES_RCODE_NOTAUTH = 9, /*!< RFC 2136. The server is not authoritative
* for the zone named in the Zone section.
*/
ARES_RCODE_NOTZONE = 10, /*!< RFC 2136. A name used in the Prerequisite
* or Update Section is not within the zone
* denoted by the Zone Section. */
ARES_RCODE_DSOTYPEI = 11, /*!< RFC 8409. DSO-TYPE Not implemented */
ARES_RCODE_BADSIG = 16, /*!< RFC 8945. TSIG Signature Failure */
ARES_RCODE_BADKEY = 17, /*!< RFC 8945. Key not recognized. */
ARES_RCODE_BADTIME = 18, /*!< RFC 8945. Signature out of time window. */
ARES_RCODE_BADMODE = 19, /*!< RFC 2930. Bad TKEY Mode */
ARES_RCODE_BADNAME = 20, /*!< RFC 2930. Duplicate Key Name */
ARES_RCODE_BADALG = 21, /*!< RFC 2930. Algorithm not supported */
ARES_RCODE_BADTRUNC = 22, /*!< RFC 8945. Bad Truncation */
ARES_RCODE_BADCOOKIE = 23 /*!< RVC 7973. Bad/missing Server Cookie */
} ares_dns_rcode_t;
/*! Data types used */
typedef enum {
ARES_DATATYPE_INADDR = 1, /*!< struct in_addr * type */
ARES_DATATYPE_INADDR6 = 2, /*!< struct ares_in6_addr * type */
ARES_DATATYPE_U8 = 3, /*!< 8bit unsigned integer */
ARES_DATATYPE_U16 = 4, /*!< 16bit unsigned integer */
ARES_DATATYPE_U32 = 5, /*!< 32bit unsigned integer */
ARES_DATATYPE_NAME = 6, /*!< Null-terminated string of a domain name */
ARES_DATATYPE_STR = 7, /*!< Null-terminated string */
ARES_DATATYPE_BIN = 8, /*!< Binary data */
ARES_DATATYPE_BINP = 9, /*!< Officially defined as binary data, but likely
* printable. Guaranteed to have a NULL
* terminator for convenience (not included in
* length) */
ARES_DATATYPE_OPT = 10, /*!< Array of options. 16bit identifier, BIN
* data. */
ARES_DATATYPE_ABINP = 11 /*!< Array of binary data, likely printable.
* Guaranteed to have a NULL terminator for
* convenience (not included in length) */
} ares_dns_datatype_t;
/*! Keys used for all RR Types. We take the record type and multiply by 100
* to ensure we have a proper offset between keys so we can keep these sorted
*/
typedef enum {
/*! A Record. Address. Datatype: INADDR */
ARES_RR_A_ADDR = (ARES_REC_TYPE_A * 100) + 1,
/*! NS Record. Name. Datatype: NAME */
ARES_RR_NS_NSDNAME = (ARES_REC_TYPE_NS * 100) + 1,
/*! CNAME Record. CName. Datatype: NAME */
ARES_RR_CNAME_CNAME = (ARES_REC_TYPE_CNAME * 100) + 1,
/*! SOA Record. MNAME, Primary Source of Data. Datatype: NAME */
ARES_RR_SOA_MNAME = (ARES_REC_TYPE_SOA * 100) + 1,
/*! SOA Record. RNAME, Mailbox of person responsible. Datatype: NAME */
ARES_RR_SOA_RNAME = (ARES_REC_TYPE_SOA * 100) + 2,
/*! SOA Record. Serial, version. Datatype: U32 */
ARES_RR_SOA_SERIAL = (ARES_REC_TYPE_SOA * 100) + 3,
/*! SOA Record. Refresh, zone refersh interval. Datatype: U32 */
ARES_RR_SOA_REFRESH = (ARES_REC_TYPE_SOA * 100) + 4,
/*! SOA Record. Retry, failed refresh retry interval. Datatype: U32 */
ARES_RR_SOA_RETRY = (ARES_REC_TYPE_SOA * 100) + 5,
/*! SOA Record. Expire, upper limit on authority. Datatype: U32 */
ARES_RR_SOA_EXPIRE = (ARES_REC_TYPE_SOA * 100) + 6,
/*! SOA Record. Minimum, RR TTL. Datatype: U32 */
ARES_RR_SOA_MINIMUM = (ARES_REC_TYPE_SOA * 100) + 7,
/*! PTR Record. DNAME, pointer domain. Datatype: NAME */
ARES_RR_PTR_DNAME = (ARES_REC_TYPE_PTR * 100) + 1,
/*! HINFO Record. CPU. Datatype: STR */
ARES_RR_HINFO_CPU = (ARES_REC_TYPE_HINFO * 100) + 1,
/*! HINFO Record. OS. Datatype: STR */
ARES_RR_HINFO_OS = (ARES_REC_TYPE_HINFO * 100) + 2,
/*! MX Record. Preference. Datatype: U16 */
ARES_RR_MX_PREFERENCE = (ARES_REC_TYPE_MX * 100) + 1,
/*! MX Record. Exchange, domain. Datatype: NAME */
ARES_RR_MX_EXCHANGE = (ARES_REC_TYPE_MX * 100) + 2,
/*! TXT Record. Data. Datatype: ABINP */
ARES_RR_TXT_DATA = (ARES_REC_TYPE_TXT * 100) + 1,
/*! SIG Record. Type Covered. Datatype: U16 */
ARES_RR_SIG_TYPE_COVERED = (ARES_REC_TYPE_SIG * 100) + 1,
/*! SIG Record. Algorithm. Datatype: U8 */
ARES_RR_SIG_ALGORITHM = (ARES_REC_TYPE_SIG * 100) + 2,
/*! SIG Record. Labels. Datatype: U8 */
ARES_RR_SIG_LABELS = (ARES_REC_TYPE_SIG * 100) + 3,
/*! SIG Record. Original TTL. Datatype: U32 */
ARES_RR_SIG_ORIGINAL_TTL = (ARES_REC_TYPE_SIG * 100) + 4,
/*! SIG Record. Signature Expiration. Datatype: U32 */
ARES_RR_SIG_EXPIRATION = (ARES_REC_TYPE_SIG * 100) + 5,
/*! SIG Record. Signature Inception. Datatype: U32 */
ARES_RR_SIG_INCEPTION = (ARES_REC_TYPE_SIG * 100) + 6,
/*! SIG Record. Key Tag. Datatype: U16 */
ARES_RR_SIG_KEY_TAG = (ARES_REC_TYPE_SIG * 100) + 7,
/*! SIG Record. Signers Name. Datatype: NAME */
ARES_RR_SIG_SIGNERS_NAME = (ARES_REC_TYPE_SIG * 100) + 8,
/*! SIG Record. Signature. Datatype: BIN */
ARES_RR_SIG_SIGNATURE = (ARES_REC_TYPE_SIG * 100) + 9,
/*! AAAA Record. Address. Datatype: INADDR6 */
ARES_RR_AAAA_ADDR = (ARES_REC_TYPE_AAAA * 100) + 1,
/*! SRV Record. Priority. Datatype: U16 */
ARES_RR_SRV_PRIORITY = (ARES_REC_TYPE_SRV * 100) + 2,
/*! SRV Record. Weight. Datatype: U16 */
ARES_RR_SRV_WEIGHT = (ARES_REC_TYPE_SRV * 100) + 3,
/*! SRV Record. Port. Datatype: U16 */
ARES_RR_SRV_PORT = (ARES_REC_TYPE_SRV * 100) + 4,
/*! SRV Record. Target domain. Datatype: NAME */
ARES_RR_SRV_TARGET = (ARES_REC_TYPE_SRV * 100) + 5,
/*! NAPTR Record. Order. Datatype: U16 */
ARES_RR_NAPTR_ORDER = (ARES_REC_TYPE_NAPTR * 100) + 1,
/*! NAPTR Record. Preference. Datatype: U16 */
ARES_RR_NAPTR_PREFERENCE = (ARES_REC_TYPE_NAPTR * 100) + 2,
/*! NAPTR Record. Flags. Datatype: STR */
ARES_RR_NAPTR_FLAGS = (ARES_REC_TYPE_NAPTR * 100) + 3,
/*! NAPTR Record. Services. Datatype: STR */
ARES_RR_NAPTR_SERVICES = (ARES_REC_TYPE_NAPTR * 100) + 4,
/*! NAPTR Record. Regexp. Datatype: STR */
ARES_RR_NAPTR_REGEXP = (ARES_REC_TYPE_NAPTR * 100) + 5,
/*! NAPTR Record. Replacement. Datatype: NAME */
ARES_RR_NAPTR_REPLACEMENT = (ARES_REC_TYPE_NAPTR * 100) + 6,
/*! OPT Record. UDP Size. Datatype: U16 */
ARES_RR_OPT_UDP_SIZE = (ARES_REC_TYPE_OPT * 100) + 1,
/*! OPT Record. Version. Datatype: U8 */
ARES_RR_OPT_VERSION = (ARES_REC_TYPE_OPT * 100) + 3,
/*! OPT Record. Flags. Datatype: U16 */
ARES_RR_OPT_FLAGS = (ARES_REC_TYPE_OPT * 100) + 4,
/*! OPT Record. Options. Datatype: OPT */
ARES_RR_OPT_OPTIONS = (ARES_REC_TYPE_OPT * 100) + 5,
/*! TLSA Record. Certificate Usage. Datatype: U8 */
ARES_RR_TLSA_CERT_USAGE = (ARES_REC_TYPE_TLSA * 100) + 1,
/*! TLSA Record. Selector. Datatype: U8 */
ARES_RR_TLSA_SELECTOR = (ARES_REC_TYPE_TLSA * 100) + 2,
/*! TLSA Record. Matching Type. Datatype: U8 */
ARES_RR_TLSA_MATCH = (ARES_REC_TYPE_TLSA * 100) + 3,
/*! TLSA Record. Certificate Association Data. Datatype: BIN */
ARES_RR_TLSA_DATA = (ARES_REC_TYPE_TLSA * 100) + 4,
/*! SVCB Record. SvcPriority. Datatype: U16 */
ARES_RR_SVCB_PRIORITY = (ARES_REC_TYPE_SVCB * 100) + 1,
/*! SVCB Record. TargetName. Datatype: NAME */
ARES_RR_SVCB_TARGET = (ARES_REC_TYPE_SVCB * 100) + 2,
/*! SVCB Record. SvcParams. Datatype: OPT */
ARES_RR_SVCB_PARAMS = (ARES_REC_TYPE_SVCB * 100) + 3,
/*! HTTPS Record. SvcPriority. Datatype: U16 */
ARES_RR_HTTPS_PRIORITY = (ARES_REC_TYPE_HTTPS * 100) + 1,
/*! HTTPS Record. TargetName. Datatype: NAME */
ARES_RR_HTTPS_TARGET = (ARES_REC_TYPE_HTTPS * 100) + 2,
/*! HTTPS Record. SvcParams. Datatype: OPT */
ARES_RR_HTTPS_PARAMS = (ARES_REC_TYPE_HTTPS * 100) + 3,
/*! URI Record. Priority. Datatype: U16 */
ARES_RR_URI_PRIORITY = (ARES_REC_TYPE_URI * 100) + 1,
/*! URI Record. Weight. Datatype: U16 */
ARES_RR_URI_WEIGHT = (ARES_REC_TYPE_URI * 100) + 2,
/*! URI Record. Target domain. Datatype: NAME */
ARES_RR_URI_TARGET = (ARES_REC_TYPE_URI * 100) + 3,
/*! CAA Record. Critical flag. Datatype: U8 */
ARES_RR_CAA_CRITICAL = (ARES_REC_TYPE_CAA * 100) + 1,
/*! CAA Record. Tag/Property. Datatype: STR */
ARES_RR_CAA_TAG = (ARES_REC_TYPE_CAA * 100) + 2,
/*! CAA Record. Value. Datatype: BINP */
ARES_RR_CAA_VALUE = (ARES_REC_TYPE_CAA * 100) + 3,
/*! RAW Record. RR Type. Datatype: U16 */
ARES_RR_RAW_RR_TYPE = (ARES_REC_TYPE_RAW_RR * 100) + 1,
/*! RAW Record. RR Data. Datatype: BIN */
ARES_RR_RAW_RR_DATA = (ARES_REC_TYPE_RAW_RR * 100) + 2
} ares_dns_rr_key_t;
/*! TLSA Record ARES_RR_TLSA_CERT_USAGE known values */
typedef enum {
/*! Certificate Usage 0. CA Constraint. */
ARES_TLSA_USAGE_CA = 0,
/*! Certificate Usage 1. Service Certificate Constraint. */
ARES_TLSA_USAGE_SERVICE = 1,
/*! Certificate Usage 2. Trust Anchor Assertion. */
ARES_TLSA_USAGE_TRUSTANCHOR = 2,
/*! Certificate Usage 3. Domain-issued certificate. */
ARES_TLSA_USAGE_DOMAIN = 3
} ares_tlsa_usage_t;
/*! TLSA Record ARES_RR_TLSA_SELECTOR known values */
typedef enum {
/*! Full Certificate */
ARES_TLSA_SELECTOR_FULL = 0,
/*! DER-encoded SubjectPublicKeyInfo */
ARES_TLSA_SELECTOR_SUBJPUBKEYINFO = 1
} ares_tlsa_selector_t;
/*! TLSA Record ARES_RR_TLSA_MATCH known values */
typedef enum {
/*! Exact match */
ARES_TLSA_MATCH_EXACT = 0,
/*! Sha256 match */
ARES_TLSA_MATCH_SHA256 = 1,
/*! Sha512 match */
ARES_TLSA_MATCH_SHA512 = 2
} ares_tlsa_match_t;
/*! SVCB (and HTTPS) RR known parameters */
typedef enum {
/*! Mandatory keys in this RR (RFC 9460 Section 8) */
ARES_SVCB_PARAM_MANDATORY = 0,
/*! Additional supported protocols (RFC 9460 Section 7.1) */
ARES_SVCB_PARAM_ALPN = 1,
/*! No support for default protocol (RFC 9460 Section 7.1) */
ARES_SVCB_PARAM_NO_DEFAULT_ALPN = 2,
/*! Port for alternative endpoint (RFC 9460 Section 7.2) */
ARES_SVCB_PARAM_PORT = 3,
/*! IPv4 address hints (RFC 9460 Section 7.3) */
ARES_SVCB_PARAM_IPV4HINT = 4,
/*! RESERVED (held for Encrypted ClientHello) */
ARES_SVCB_PARAM_ECH = 5,
/*! IPv6 address hints (RFC 9460 Section 7.3) */
ARES_SVCB_PARAM_IPV6HINT = 6
} ares_svcb_param_t;
/*! OPT RR known parameters */
typedef enum {
/*! RFC 8764. Apple's DNS Long-Lived Queries Protocol */
ARES_OPT_PARAM_LLQ = 1,
/*! http://files.dns-sd.org/draft-sekar-dns-ul.txt: Update Lease */
ARES_OPT_PARAM_UL = 2,
/*! RFC 5001. Name Server Identification */
ARES_OPT_PARAM_NSID = 3,
/*! RFC 6975. DNSSEC Algorithm Understood */
ARES_OPT_PARAM_DAU = 5,
/*! RFC 6975. DS Hash Understood */
ARES_OPT_PARAM_DHU = 6,
/*! RFC 6975. NSEC3 Hash Understood */
ARES_OPT_PARAM_N3U = 7,
/*! RFC 7871. Client Subnet */
ARES_OPT_PARAM_EDNS_CLIENT_SUBNET = 8,
/*! RFC 7314. Expire Timer */
ARES_OPT_PARAM_EDNS_EXPIRE = 9,
/*! RFC 7873. Client and Server Cookies */
ARES_OPT_PARAM_COOKIE = 10,
/*! RFC 7828. TCP Keepalive timeout */
ARES_OPT_PARAM_EDNS_TCP_KEEPALIVE = 11,
/*! RFC 7830. Padding */
ARES_OPT_PARAM_PADDING = 12,
/*! RFC 7901. Chain query requests */
ARES_OPT_PARAM_CHAIN = 13,
/*! RFC 8145. Signaling Trust Anchor Knowledge in DNSSEC */
ARES_OPT_PARAM_EDNS_KEY_TAG = 14,
/*! RFC 8914. Extended ERROR code and message */
ARES_OPT_PARAM_EXTENDED_DNS_ERROR = 15
} ares_opt_param_t;
/*! Data type for option records for keys like ARES_RR_OPT_OPTIONS and
* ARES_RR_HTTPS_PARAMS returned by ares_dns_opt_get_datatype() */
typedef enum {
/*! No value allowed for this option */
ARES_OPT_DATATYPE_NONE = 1,
/*! List of strings, each prefixed with a single octet representing the length
*/
ARES_OPT_DATATYPE_STR_LIST = 2,
/*! List of 8bit integers, concatenated */
ARES_OPT_DATATYPE_U8_LIST = 3,
/*! 16bit integer in network byte order */
ARES_OPT_DATATYPE_U16 = 4,
/*! list of 16bit integer in network byte order, concatenated. */
ARES_OPT_DATATYPE_U16_LIST = 5,
/*! 32bit integer in network byte order */
ARES_OPT_DATATYPE_U32 = 6,
/*! list 32bit integer in network byte order, concatenated */
ARES_OPT_DATATYPE_U32_LIST = 7,
/*! List of ipv4 addresses in network byte order, concatenated */
ARES_OPT_DATATYPE_INADDR4_LIST = 8,
/*! List of ipv6 addresses in network byte order, concatenated */
ARES_OPT_DATATYPE_INADDR6_LIST = 9,
/*! Binary Data */
ARES_OPT_DATATYPE_BIN = 10,
/*! DNS Domain Name Format */
ARES_OPT_DATATYPE_NAME = 11
} ares_dns_opt_datatype_t;
/*! Data type for flags to ares_dns_parse() */
typedef enum {
/*! Parse Answers from RFC 1035 that allow name compression as RAW */
ARES_DNS_PARSE_AN_BASE_RAW = 1 << 0,
/*! Parse Authority from RFC 1035 that allow name compression as RAW */
ARES_DNS_PARSE_NS_BASE_RAW = 1 << 1,
/*! Parse Additional from RFC 1035 that allow name compression as RAW */
ARES_DNS_PARSE_AR_BASE_RAW = 1 << 2,
/*! Parse Answers from later RFCs (no name compression) RAW */
ARES_DNS_PARSE_AN_EXT_RAW = 1 << 3,
/*! Parse Authority from later RFCs (no name compression) as RAW */
ARES_DNS_PARSE_NS_EXT_RAW = 1 << 4,
/*! Parse Additional from later RFCs (no name compression) as RAW */
ARES_DNS_PARSE_AR_EXT_RAW = 1 << 5
} ares_dns_parse_flags_t;
/*! String representation of DNS Record Type
*
* \param[in] type DNS Record Type
* \return string
*/
CARES_EXTERN const char *ares_dns_rec_type_tostr(ares_dns_rec_type_t type);
/*! String representation of DNS Class
*
* \param[in] qclass DNS Class
* \return string
*/
CARES_EXTERN const char *ares_dns_class_tostr(ares_dns_class_t qclass);
/*! String representation of DNS OpCode
*
* \param[in] opcode DNS OpCode
* \return string
*/
CARES_EXTERN const char *ares_dns_opcode_tostr(ares_dns_opcode_t opcode);
/*! String representation of DNS Resource Record Parameter
*
* \param[in] key DNS Resource Record parameter
* \return string
*/
CARES_EXTERN const char *ares_dns_rr_key_tostr(ares_dns_rr_key_t key);
/*! String representation of DNS Resource Record section
*
* \param[in] section Section
* \return string
*/
CARES_EXTERN const char *ares_dns_section_tostr(ares_dns_section_t section);
/*! Convert DNS class name as string to ares_dns_class_t
*
* \param[out] qclass Pointer passed by reference to write class
* \param[in] str String to convert
* \return ARES_TRUE on success
*/
CARES_EXTERN ares_bool_t ares_dns_class_fromstr(ares_dns_class_t *qclass,
const char *str);
/*! Convert DNS record type as string to ares_dns_rec_type_t
*
* \param[out] qtype Pointer passed by reference to write record type
* \param[in] str String to convert
* \return ARES_TRUE on success
*/
CARES_EXTERN ares_bool_t ares_dns_rec_type_fromstr(ares_dns_rec_type_t *qtype,
const char *str);
/*! Convert DNS response code as string to from ares_dns_rcode_t
*
* \param[in] rcode Response code to convert
* \return ARES_TRUE on success
*/
CARES_EXTERN const char *ares_dns_rcode_tostr(ares_dns_rcode_t rcode);
/*! Convert any valid ip address (ipv4 or ipv6) into struct ares_addr and
* return the starting pointer of the network byte order address and the
* length of the address (4 or 16).
*
* \param[in] ipaddr ASCII string form of the ip address
* \param[in,out] addr Must set "family" member to one of AF_UNSPEC,
* AF_INET, AF_INET6 on input.
* \param[out] out_len Length of binary form address
* \return Pointer to start of binary address or NULL on error.
*/
CARES_EXTERN const void *ares_dns_pton(const char *ipaddr,
struct ares_addr *addr, size_t *out_len);
/*! Convert an ip address into the PTR format for in-addr.arpa or in6.arpa
*
* \param[in] addr properly filled address structure
* \return String representing PTR, use ares_free_string() to free
*/
CARES_EXTERN char *ares_dns_addr_to_ptr(const struct ares_addr *addr);
/*! The options/parameters extensions to some RRs can be somewhat opaque, this
* is a helper to return the best match for a datatype for interpreting the
* option record.
*
* \param[in] key Key associated with options/parameters
* \param[in] opt Option Key/Parameter
* \return Datatype
*/
CARES_EXTERN ares_dns_opt_datatype_t
ares_dns_opt_get_datatype(ares_dns_rr_key_t key, unsigned short opt);
/*! The options/parameters extensions to some RRs can be somewhat opaque, this
* is a helper to return the name if the option is known.
*
* \param[in] key Key associated with options/parameters
* \param[in] opt Option Key/Parameter
* \return name, or NULL if not known.
*/
CARES_EXTERN const char *ares_dns_opt_get_name(ares_dns_rr_key_t key,
unsigned short opt);
/*! Retrieve a list of Resource Record keys that can be set or retrieved for
* the Resource record type.
*
* \param[in] type Record Type
* \param[out] cnt Number of keys returned
* \return array of keys associated with Resource Record
*/
CARES_EXTERN const ares_dns_rr_key_t *
ares_dns_rr_get_keys(ares_dns_rec_type_t type, size_t *cnt);
/*! Retrieve the datatype associated with a Resource Record key.
*
* \param[in] key Resource Record Key
* \return datatype
*/
CARES_EXTERN ares_dns_datatype_t
ares_dns_rr_key_datatype(ares_dns_rr_key_t key);
/*! Retrieve the DNS Resource Record type associated with a Resource Record key.
*
* \param[in] key Resource Record Key
* \return DNS Resource Record Type
*/
CARES_EXTERN ares_dns_rec_type_t
ares_dns_rr_key_to_rec_type(ares_dns_rr_key_t key);
/*! Opaque data type representing a DNS RR (Resource Record) */
struct ares_dns_rr;
/*! Typedef for opaque data type representing a DNS RR (Resource Record) */
typedef struct ares_dns_rr ares_dns_rr_t;
/*! Opaque data type representing a DNS Query Data QD Packet */
struct ares_dns_qd;
/*! Typedef for opaque data type representing a DNS Query Data QD Packet */
typedef struct ares_dns_qd ares_dns_qd_t;
/*! Opaque data type representing a DNS Packet */
struct ares_dns_record;
/*! Typedef for opaque data type representing a DNS Packet */
typedef struct ares_dns_record ares_dns_record_t;
/*! Create a new DNS record object
*
* \param[out] dnsrec Pointer passed by reference for a newly allocated
* record object. Must be ares_dns_record_destroy()'d by
* caller.
* \param[in] id DNS Query ID. If structuring a new query to be sent
* with ares_send(), this value should be zero.
* \param[in] flags DNS Flags from \ares_dns_flags_t
* \param[in] opcode DNS OpCode (typically ARES_OPCODE_QUERY)
* \param[in] rcode DNS RCode
* \return ARES_SUCCESS on success
*/
CARES_EXTERN ares_status_t ares_dns_record_create(ares_dns_record_t **dnsrec,
unsigned short id,
unsigned short flags,
ares_dns_opcode_t opcode,
ares_dns_rcode_t rcode);
/*! Destroy a DNS record object
*
* \param[in] dnsrec Initialized record object
*/
CARES_EXTERN void ares_dns_record_destroy(ares_dns_record_t *dnsrec);
/*! Get the DNS Query ID
*
* \param[in] dnsrec Initialized record object
* \return DNS query id
*/
CARES_EXTERN unsigned short
ares_dns_record_get_id(const ares_dns_record_t *dnsrec);
/*! Overwrite the DNS query id
*
* \param[in] dnsrec Initialized record object
* \param[in] id DNS query id
* \return ARES_TRUE on success, ARES_FALSE on usage error
*/
CARES_EXTERN ares_bool_t
ares_dns_record_set_id(ares_dns_record_t *dnsrec, unsigned short id);
/*! Get the DNS Record Flags
*
* \param[in] dnsrec Initialized record object
* \return One or more \ares_dns_flags_t
*/
CARES_EXTERN unsigned short
ares_dns_record_get_flags(const ares_dns_record_t *dnsrec);
/*! Get the DNS Record OpCode
*
* \param[in] dnsrec Initialized record object
* \return opcode
*/
CARES_EXTERN ares_dns_opcode_t
ares_dns_record_get_opcode(const ares_dns_record_t *dnsrec);
/*! Get the DNS Record RCode
*
* \param[in] dnsrec Initialized record object
* \return rcode
*/
CARES_EXTERN ares_dns_rcode_t
ares_dns_record_get_rcode(const ares_dns_record_t *dnsrec);
/*! Add a query to the DNS Record. Typically a record will have only 1
* query. Most DNS servers will reject queries with more than 1 question.
*
* \param[in] dnsrec Initialized record object
* \param[in] name Name/Hostname of request
* \param[in] qtype Type of query
* \param[in] qclass Class of query (typically ARES_CLASS_IN)
* \return ARES_SUCCESS on success
*/
CARES_EXTERN ares_status_t ares_dns_record_query_add(ares_dns_record_t *dnsrec,
const char *name,
ares_dns_rec_type_t qtype,
ares_dns_class_t qclass);
/*! Replace the question name with a new name. This may be used when performing
* a search with aliases.
*
* Note that this will invalidate the name pointer returned from
* ares_dns_record_query_get().
*
* \param[in] dnsrec Initialized record object
* \param[in] idx Index of question (typically 0)
* \param[in] name Name to use as replacement.
* \return ARES_SUCCESS on success
*/
CARES_EXTERN ares_status_t ares_dns_record_query_set_name(
ares_dns_record_t *dnsrec, size_t idx, const char *name);
/*! Replace the question type with a different type. This may be used when
* needing to query more than one address class (e.g. A and AAAA)
*
* \param[in] dnsrec Initialized record object
* \param[in] idx Index of question (typically 0)
* \param[in] qtype Record Type to use as replacement.
* \return ARES_SUCCESS on success
*/
CARES_EXTERN ares_status_t ares_dns_record_query_set_type(
ares_dns_record_t *dnsrec, size_t idx, ares_dns_rec_type_t qtype);
/*! Get the count of queries in the DNS Record
*
* \param[in] dnsrec Initialized record object
* \return count of queries
*/
CARES_EXTERN size_t ares_dns_record_query_cnt(const ares_dns_record_t *dnsrec);
/*! Get the data about the query at the provided index.
*
* \param[in] dnsrec Initialized record object
* \param[in] idx Index of query
* \param[out] name Optional. Returns name, may pass NULL if not desired.
* This pointer will be invalided by any call to
* ares_dns_record_query_set_name().
* \param[out] qtype Optional. Returns record type, may pass NULL.
* \param[out] qclass Optional. Returns class, may pass NULL.
* \return ARES_SUCCESS on success
*/
CARES_EXTERN ares_status_t ares_dns_record_query_get(
const ares_dns_record_t *dnsrec, size_t idx, const char **name,
ares_dns_rec_type_t *qtype, ares_dns_class_t *qclass);
/*! Get the count of Resource Records in the provided section
*
* \param[in] dnsrec Initialized record object
* \param[in] sect Section. ARES_SECTION_ANSWER is most used.
* \return count of resource records.
*/
CARES_EXTERN size_t ares_dns_record_rr_cnt(const ares_dns_record_t *dnsrec,
ares_dns_section_t sect);
/*! Add a Resource Record to the DNS Record.
*
* \param[out] rr_out Pointer to created resource record. This pointer
* is owned by the DNS record itself, this is just made
* available to facilitate adding RR-specific fields.
* \param[in] dnsrec Initialized record object
* \param[in] sect Section to add resource record to
* \param[in] name Resource Record name/hostname
* \param[in] type Record Type
* \param[in] rclass Class
* \param[in] ttl TTL
* \return ARES_SUCCESS on success
*/
CARES_EXTERN ares_status_t ares_dns_record_rr_add(
ares_dns_rr_t **rr_out, ares_dns_record_t *dnsrec, ares_dns_section_t sect,
const char *name, ares_dns_rec_type_t type, ares_dns_class_t rclass,
unsigned int ttl);
/*! Fetch a writable resource record based on the section and index.
*
* \param[in] dnsrec Initialized record object
* \param[in] sect Section for resource record
* \param[in] idx Index of resource record in section
* \return NULL on misuse, otherwise a writable pointer to the resource record
*/
CARES_EXTERN ares_dns_rr_t *ares_dns_record_rr_get(ares_dns_record_t *dnsrec,
ares_dns_section_t sect,
size_t idx);
/*! Fetch a non-writeable resource record based on the section and index.
*
* \param[in] dnsrec Initialized record object
* \param[in] sect Section for resource record
* \param[in] idx Index of resource record in section
* \return NULL on misuse, otherwise a const pointer to the resource record
*/
CARES_EXTERN const ares_dns_rr_t *
ares_dns_record_rr_get_const(const ares_dns_record_t *dnsrec,
ares_dns_section_t sect, size_t idx);
/*! Remove the resource record based on the section and index
*
* \param[in] dnsrec Initialized record object
* \param[in] sect Section for resource record
* \param[in] idx Index of resource record in section
* \return ARES_SUCCESS on success, otherwise an error code.
*/
CARES_EXTERN ares_status_t ares_dns_record_rr_del(ares_dns_record_t *dnsrec,
ares_dns_section_t sect,
size_t idx);
/*! Retrieve the resource record Name/Hostname
*
* \param[in] rr Pointer to resource record
* \return Name
*/
CARES_EXTERN const char *ares_dns_rr_get_name(const ares_dns_rr_t *rr);
/*! Retrieve the resource record type
*
* \param[in] rr Pointer to resource record
* \return type
*/
CARES_EXTERN ares_dns_rec_type_t ares_dns_rr_get_type(const ares_dns_rr_t *rr);
/*! Retrieve the resource record class
*
* \param[in] rr Pointer to resource record
* \return class
*/
CARES_EXTERN ares_dns_class_t ares_dns_rr_get_class(const ares_dns_rr_t *rr);
/*! Retrieve the resource record TTL
*
* \param[in] rr Pointer to resource record
* \return TTL
*/
CARES_EXTERN unsigned int ares_dns_rr_get_ttl(const ares_dns_rr_t *rr);
/*! Set ipv4 address data type for specified resource record and key. Can
* only be used on keys with datatype ARES_DATATYPE_INADDR
*
* \param[in] dns_rr Pointer to resource record
* \param[in] key DNS Resource Record Key
* \param[in] addr Pointer to ipv4 address to use.
* \return ARES_SUCCESS on success
*/
CARES_EXTERN ares_status_t ares_dns_rr_set_addr(ares_dns_rr_t *dns_rr,
ares_dns_rr_key_t key,
const struct in_addr *addr);
/*! Set ipv6 address data type for specified resource record and key. Can
* only be used on keys with datatype ARES_DATATYPE_INADDR6
*
* \param[in] dns_rr Pointer to resource record
* \param[in] key DNS Resource Record Key
* \param[in] addr Pointer to ipv6 address to use.
* \return ARES_SUCCESS on success
*/
CARES_EXTERN ares_status_t
ares_dns_rr_set_addr6(ares_dns_rr_t *dns_rr, ares_dns_rr_key_t key,
const struct ares_in6_addr *addr);
/*! Set string data for specified resource record and key. Can
* only be used on keys with datatype ARES_DATATYPE_STR or ARES_DATATYPE_NAME.
*
* \param[in] dns_rr Pointer to resource record
* \param[in] key DNS Resource Record Key
* \param[in] val Pointer to string to set.
* \return ARES_SUCCESS on success
*/
CARES_EXTERN ares_status_t ares_dns_rr_set_str(ares_dns_rr_t *dns_rr,
ares_dns_rr_key_t key,
const char *val);
/*! Set 8bit unsigned integer for specified resource record and key. Can
* only be used on keys with datatype ARES_DATATYPE_U8
*
* \param[in] dns_rr Pointer to resource record
* \param[in] key DNS Resource Record Key
* \param[in] val 8bit unsigned integer
* \return ARES_SUCCESS on success
*/
CARES_EXTERN ares_status_t ares_dns_rr_set_u8(ares_dns_rr_t *dns_rr,
ares_dns_rr_key_t key,
unsigned char val);
/*! Set 16bit unsigned integer for specified resource record and key. Can
* only be used on keys with datatype ARES_DATATYPE_U16
*
* \param[in] dns_rr Pointer to resource record
* \param[in] key DNS Resource Record Key
* \param[in] val 16bit unsigned integer
* \return ARES_SUCCESS on success
*/
CARES_EXTERN ares_status_t ares_dns_rr_set_u16(ares_dns_rr_t *dns_rr,
ares_dns_rr_key_t key,
unsigned short val);
/*! Set 32bit unsigned integer for specified resource record and key. Can
* only be used on keys with datatype ARES_DATATYPE_U32
*
* \param[in] dns_rr Pointer to resource record
* \param[in] key DNS Resource Record Key
* \param[in] val 32bit unsigned integer
* \return ARES_SUCCESS on success
*/
CARES_EXTERN ares_status_t ares_dns_rr_set_u32(ares_dns_rr_t *dns_rr,
ares_dns_rr_key_t key,
unsigned int val);
/*! Set binary (BIN or BINP) data for specified resource record and key. Can
* only be used on keys with datatype ARES_DATATYPE_BIN or ARES_DATATYPE_BINP.
*
* \param[in] dns_rr Pointer to resource record
* \param[in] key DNS Resource Record Key
* \param[in] val Pointer to binary data.
* \param[in] len Length of binary data
* \return ARES_SUCCESS on success
*/
CARES_EXTERN ares_status_t ares_dns_rr_set_bin(ares_dns_rr_t *dns_rr,
ares_dns_rr_key_t key,
const unsigned char *val,
size_t len);
/*! Add binary array value (ABINP) data for specified resource record and key.
* Can only be used on keys with datatype ARES_DATATYPE_ABINP. The value will
* Be added as the last element in the array.
*
* \param[in] dns_rr Pointer to resource record
* \param[in] key DNS Resource Record Key
* \param[in] val Pointer to binary data.
* \param[in] len Length of binary data
* \return ARES_SUCCESS on success
*/
CARES_EXTERN ares_status_t ares_dns_rr_add_abin(ares_dns_rr_t *dns_rr,
ares_dns_rr_key_t key,
const unsigned char *val,
size_t len);
/*! Delete binary array value (ABINP) data for specified resource record and
* key by specified index. Can only be used on keys with datatype
* ARES_DATATYPE_ABINP. The value at the index will be deleted.
*
* \param[in] dns_rr Pointer to resource record
* \param[in] key DNS Resource Record Key
* \param[in] idx Index to delete
* \return ARES_SUCCESS on success
*/
CARES_EXTERN ares_status_t ares_dns_rr_del_abin(ares_dns_rr_t *dns_rr,
ares_dns_rr_key_t key,
size_t idx);
/*! Set the option for the RR
*
* \param[in] dns_rr Pointer to resource record
* \param[in] key DNS Resource Record Key
* \param[in] opt Option record key id.
* \param[out] val Optional. Value to associate with option.
* \param[out] val_len Length of value passed.
* \return ARES_SUCCESS on success
*/
CARES_EXTERN ares_status_t ares_dns_rr_set_opt(ares_dns_rr_t *dns_rr,
ares_dns_rr_key_t key,
unsigned short opt,
const unsigned char *val,
size_t val_len);
/*! Retrieve a pointer to the ipv4 address. Can only be used on keys with
* datatype ARES_DATATYPE_INADDR.
*
* \param[in] dns_rr Pointer to resource record
* \param[in] key DNS Resource Record Key
* \return pointer to ipv4 address or NULL on error
*/
CARES_EXTERN const struct in_addr *
ares_dns_rr_get_addr(const ares_dns_rr_t *dns_rr, ares_dns_rr_key_t key);
/*! Retrieve a pointer to the ipv6 address. Can only be used on keys with
* datatype ARES_DATATYPE_INADDR6.
*
* \param[in] dns_rr Pointer to resource record
* \param[in] key DNS Resource Record Key
* \return pointer to ipv6 address or NULL on error
*/
CARES_EXTERN const struct ares_in6_addr *
ares_dns_rr_get_addr6(const ares_dns_rr_t *dns_rr, ares_dns_rr_key_t key);
/*! Retrieve a pointer to the string. Can only be used on keys with
* datatype ARES_DATATYPE_STR and ARES_DATATYPE_NAME.
*
* \param[in] dns_rr Pointer to resource record
* \param[in] key DNS Resource Record Key
* \return pointer string or NULL on error
*/
CARES_EXTERN const char *ares_dns_rr_get_str(const ares_dns_rr_t *dns_rr,
ares_dns_rr_key_t key);
/*! Retrieve an 8bit unsigned integer. Can only be used on keys with
* datatype ARES_DATATYPE_U8.
*
* \param[in] dns_rr Pointer to resource record
* \param[in] key DNS Resource Record Key
* \return 8bit unsigned integer
*/
CARES_EXTERN unsigned char ares_dns_rr_get_u8(const ares_dns_rr_t *dns_rr,
ares_dns_rr_key_t key);
/*! Retrieve an 16bit unsigned integer. Can only be used on keys with
* datatype ARES_DATATYPE_U16.
*
* \param[in] dns_rr Pointer to resource record
* \param[in] key DNS Resource Record Key
* \return 16bit unsigned integer
*/
CARES_EXTERN unsigned short ares_dns_rr_get_u16(const ares_dns_rr_t *dns_rr,
ares_dns_rr_key_t key);
/*! Retrieve an 32bit unsigned integer. Can only be used on keys with
* datatype ARES_DATATYPE_U32.
*
* \param[in] dns_rr Pointer to resource record
* \param[in] key DNS Resource Record Key
* \return 32bit unsigned integer
*/
CARES_EXTERN unsigned int ares_dns_rr_get_u32(const ares_dns_rr_t *dns_rr,
ares_dns_rr_key_t key);
/*! Retrieve a pointer to the binary data. Can only be used on keys with
* datatype ARES_DATATYPE_BIN, ARES_DATATYPE_BINP, or ARES_DATATYPE_ABINP.
* If BINP or ABINP, the data is guaranteed to have a NULL terminator which
* is NOT included in the length.
*
* \param[in] dns_rr Pointer to resource record
* \param[in] key DNS Resource Record Key
* \param[out] len Length of binary data returned
* \return pointer binary data or NULL on error
*/
CARES_EXTERN const unsigned char *
ares_dns_rr_get_bin(const ares_dns_rr_t *dns_rr, ares_dns_rr_key_t key,
size_t *len);
/*! Retrieve the count of the array of stored binary values. Can only be used on
* keys with datatype ARES_DATATYPE_ABINP.
*
* \param[in] dns_rr Pointer to resource record
* \param[in] key DNS Resource Record Key
* \return count of values
*/
CARES_EXTERN size_t ares_dns_rr_get_abin_cnt(const ares_dns_rr_t *dns_rr,
ares_dns_rr_key_t key);
/*! Retrieve a pointer to the binary array data from the specified index. Can
* only be used on keys with datatype ARES_DATATYPE_ABINP. If ABINP, the data
* is guaranteed to have a NULL terminator which is NOT included in the length.
* If want all array membersconcatenated, may use ares_dns_rr_get_bin()
* instead.
*
* \param[in] dns_rr Pointer to resource record
* \param[in] key DNS Resource Record Key
* \param[in] idx Index of value to retrieve
* \param[out] len Length of binary data returned
* \return pointer binary data or NULL on error
*/
CARES_EXTERN const unsigned char *ares_dns_rr_get_abin(
const ares_dns_rr_t *dns_rr, ares_dns_rr_key_t key, size_t idx, size_t *len);
/*! Retrieve the number of options stored for the RR.
*
* \param[in] dns_rr Pointer to resource record
* \param[in] key DNS Resource Record Key
* \return count, or 0 if none.
*/
CARES_EXTERN size_t ares_dns_rr_get_opt_cnt(const ares_dns_rr_t *dns_rr,
ares_dns_rr_key_t key);
/*! Retrieve the option for the RR by index.
*
* \param[in] dns_rr Pointer to resource record
* \param[in] key DNS Resource Record Key
* \param[in] idx Index of option record
* \param[out] val Optional. Pointer passed by reference to hold value.
* Options may not have values. Value if returned is
* guaranteed to be NULL terminated, however in most
* cases it is not printable.
* \param[out] val_len Optional. Pointer passed by reference to hold value
* length.
* \return option key/id on success, 65535 on misuse.
*/
CARES_EXTERN unsigned short
ares_dns_rr_get_opt(const ares_dns_rr_t *dns_rr, ares_dns_rr_key_t key,
size_t idx, const unsigned char **val, size_t *val_len);
/*! Retrieve the option for the RR by the option key/id.
*
* \param[in] dns_rr Pointer to resource record
* \param[in] key DNS Resource Record Key
* \param[in] opt Option record key id (this is not the index).
* \param[out] val Optional. Pointer passed by reference to hold value.
* Options may not have values. Value if returned is
* guaranteed to be NULL terminated, however in most cases
* it is not printable.
* \param[out] val_len Optional. Pointer passed by reference to hold value
* length.
* \return ARES_TRUE on success, ARES_FALSE on misuse.
*/
CARES_EXTERN ares_bool_t ares_dns_rr_get_opt_byid(const ares_dns_rr_t *dns_rr,
ares_dns_rr_key_t key,
unsigned short opt,
const unsigned char **val,
size_t *val_len);
/*! Parse a complete DNS message.
*
* \param[in] buf pointer to bytes to be parsed
* \param[in] buf_len Length of buf provided
* \param[in] flags Flags dictating how the message should be parsed.
* \param[out] dnsrec Pointer passed by reference for a new DNS record object
* that must be ares_dns_record_destroy()'d by caller.
* \return ARES_SUCCESS on success
*/
CARES_EXTERN ares_status_t ares_dns_parse(const unsigned char *buf,
size_t buf_len, unsigned int flags,
ares_dns_record_t **dnsrec);
/*! Write a complete DNS message
*
* \param[in] dnsrec Pointer to initialized and filled DNS record object.
* \param[out] buf Pointer passed by reference to be filled in with with
* DNS message. Must be ares_free()'d by caller.
* \param[out] buf_len Length of returned buffer containing DNS message.
* \return ARES_SUCCESS on success
*/
CARES_EXTERN ares_status_t ares_dns_write(const ares_dns_record_t *dnsrec,
unsigned char **buf, size_t *buf_len);
/*! Duplicate a complete DNS message. This does not copy internal members
* (such as the ttl decrement capability).
*
* \param[in] dnsrec Pointer to initialized and filled DNS record object.
* \return duplicted DNS record object, or NULL on out of memory.
*/
CARES_EXTERN ares_dns_record_t *
ares_dns_record_duplicate(const ares_dns_record_t *dnsrec);
/*! @} */
#ifdef __cplusplus
}
#endif
#endif /* __ARES_DNS_RECORD_H */