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300 lines
10 KiB
300 lines
10 KiB
.\" Copyright (C) 2023 The c-ares project and its contributors. |
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.\" SPDX-License-Identifier: MIT |
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.\" |
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.TH ARES_DNS_MAPPINGS 3 "12 November 2023" |
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.SH NAME |
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ares_dns_class_fromstr, ares_dns_class_tostr, ares_dns_datatype_t, ares_dns_opcode_tostr, |
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ares_dns_opt_datatype_t, ares_dns_opt_get_datatype, ares_dns_opt_get_name, |
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ares_dns_rcode_tostr, ares_dns_rec_type_fromstr, ares_dns_rr_get_keys, |
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ares_dns_rr_key_datatype, ares_dns_rr_key_to_rec_type, ares_dns_rr_key_tostr, |
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ares_dns_section_tostr, ares_opt_param_t, ares_svcb_param_t \- |
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Helper functions for converting dns record identifiers to and from their |
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respective types, as well identifying datatypes for various records. |
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.SH SYNOPSIS |
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.nf |
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#include <ares.h> |
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const char *ares_dns_rec_type_tostr(ares_dns_rec_type_t type); |
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const char *ares_dns_class_tostr(ares_dns_class_t qclass); |
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const char *ares_dns_opcode_tostr(ares_dns_opcode_t opcode); |
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const char *ares_dns_rr_key_tostr(ares_dns_rr_key_t key); |
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const char *ares_dns_section_tostr(ares_dns_section_t section); |
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const char *ares_dns_rcode_tostr(ares_dns_rcode_t rcode); |
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ares_bool_t ares_dns_class_fromstr(ares_dns_class_t *qclass, const char *str); |
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ares_bool_t ares_dns_rec_type_fromstr(ares_dns_rec_type_t *qtype, |
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const char *str); |
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const ares_dns_rr_key_t *ares_dns_rr_get_keys(ares_dns_rec_type_t type, |
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size_t *cnt); |
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ares_dns_datatype_t ares_dns_rr_key_datatype(ares_dns_rr_key_t key); |
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ares_dns_rec_type_t ares_dns_rr_key_to_rec_type(ares_dns_rr_key_t key); |
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ares_dns_opt_datatype_t ares_dns_opt_get_datatype(ares_dns_rr_key_t key, |
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unsigned short opt); |
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const char *ares_dns_opt_get_name(ares_dns_rr_key_t key, unsigned short opt); |
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.fi |
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.SH ENUMERATIONS |
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.B ares_dns_datatype_t - |
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Data types associated with \fIares_dns_rr_key_t\fP: |
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.RS 4 |
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.B ARES_DATATYPE_INADDR |
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- IPv4 address as \fIstruct in_addr *\fP. Use \fIares_dns_rr_set_addr(3)\fP to |
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set and \fIares_dns_rr_get_addr(3)\fP to get. |
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.br |
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.B ARES_DATATYPE_INADDR6 |
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- IPv6 address as \fIstruct ares_in6_addr *\fP. Use \fIares_dns_rr_set_addr6(3)\fP to |
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set and \fIares_dns_rr_get_addr6(3)\fP to get. |
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.br |
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.B ARES_DATATYPE_U8 |
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- 8bit unsigned integer. Use \fIares_dns_rr_set_u8(3)\fP to |
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set and \fIares_dns_rr_get_u8(3)\fP to get. |
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.br |
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.B ARES_DATATYPE_U16 |
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- 16bit unsigned integer. Use \fIares_dns_rr_set_u16(3)\fP to |
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set and \fIares_dns_rr_get_u16(3)\fP to get. |
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.br |
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.B ARES_DATATYPE_U32 |
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- 32bit unsigned integer. Use \fIares_dns_rr_set_u32(3)\fP to |
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set and \fIares_dns_rr_get_u32(3)\fP to get. |
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.br |
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.B ARES_DATATYPE_NAME |
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- Null-terminated string of a domain name (series of labels). Use \fIares_dns_rr_set_str(3)\fP to |
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set and \fIares_dns_rr_get_str(3)\fP to get. |
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.br |
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.B ARES_DATATYPE_STR |
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- Null-terminated string. Use \fIares_dns_rr_set_str(3)\fP to |
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set and \fIares_dns_rr_get_str(3)\fP to get. |
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.br |
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.B ARES_DATATYPE_BIN |
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- Binary Data. Use \fIares_dns_rr_set_bin(3)\fP to |
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set and \fIares_dns_rr_get_bin(3)\fP to get. |
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.br |
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.B ARES_DATATYPE_BINP |
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- Officially defined as binary data, but likely printable. Guaranteed to have |
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a NULL terminator for convenience (not included in length). Use \fIares_dns_rr_set_bin(3)\fP to |
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set and \fIares_dns_rr_get_bin(3)\fP to get. |
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.br |
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.B ARES_DATATYPE_OPT |
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- Array of options. 16bit identifier, Binary data. Use \fIares_dns_rr_set_opt(3)\fP to |
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set and \fIares_dns_rr_get_opt(3)\fP to get. |
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.br |
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.RE |
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.B ares_dns_opt_datatype_t - |
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Data types associated with \fIARES_DATATYPE_OPT\fP parameters if known as returned |
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by \fIares_dns_opt_get_datatype(3)\fP: |
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.RS 4 |
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.B ARES_OPT_DATATYPE_NONE |
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- No value allowed for this parameter |
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.br |
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.B ARES_OPT_DATATYPE_STR_LIST |
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- List of strings, each prefixed with a single octet representing the length as |
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defined by RFC 1035. Can use \fIares_expand_string(3)\fP until buffer is consumed. |
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.br |
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.B ARES_OPT_DATATYPE_U8_LIST |
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- List of 8bit unsigned integers, concatenated |
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.br |
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.B ARES_OPT_DATATYPE_U16 |
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- 16bit unsigned integer in network byte order |
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.br |
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.B ARES_OPT_DATATYPE_U16_LIST |
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- list of 16bit unsigned integers in network byte order, concatenated. |
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.br |
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.B ARES_OPT_DATATYPE_U32 |
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- 32bit unsigned integer in network byte order |
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.br |
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.B ARES_OPT_DATATYPE_U32_LIST |
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- list of 16bit unsigned integers in network byte order, concatenated. |
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.br |
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.B ARES_OPT_DATATYPE_INADDR4_LIST |
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- List of ipv4 addresses in network byte order, concatenated |
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.br |
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.B ARES_OPT_DATATYPE_INADDR6_LIST |
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- List of ipv6 addresses in network byte order, concatenated |
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.br |
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.B ARES_OPT_DATATYPE_BIN |
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- Binary Data |
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.br |
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.B ARES_OPT_DATATYPE_NAME |
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- DNS Domain Name binary format as defined in RFC1035, can use \fIares_expand_name(3)\fP |
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.br |
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.RE |
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.B ares_svcb_param_t - |
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SVCB (and HTTPS) RR known parameters as returned by \fIares_dns_opt_get_datatype(3)\fP |
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with \fIARES_RR_SVCB_PARAMS\fP or \fIARES_RR_HTTPS_PARAMS\fP: |
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.RS 4 |
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.B ARES_SVCB_PARAM_MANDATORY |
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- Mandatory keys in this RR (RFC 9460 Section 8). Datatype: \fIARES_OPT_DATATYPE_U16_LIST\fP |
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.br |
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.B ARES_SVCB_PARAM_ALPN |
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- Additional supported protocols (RFC 9460 Section 7.1). Datatype: \fIARES_OPT_DATATYPE_STR_LIST\fP |
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.br |
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.B ARES_SVCB_PARAM_NO_DEFAULT_ALPN |
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- No support for default protocol (RFC 9460 Section 7.1). Datatype: \fIARES_OPT_DATATYPE_NONE\fP |
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.br |
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.B ARES_SVCB_PARAM_PORT |
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- Port for alternative endpoint (RFC 9460 Section 7.2). Datatype: \fIARES_OPT_DATATYPE_U16\fP |
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.br |
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.B ARES_SVCB_PARAM_IPV4HINT |
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- IPv4 address hints (RFC 9460 Section 7.3). Datatype: \fIARES_OPT_DATATYPE_INADDR4_LIST\fP |
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.br |
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.B ARES_SVCB_PARAM_ECH |
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- RESERVED (held for Encrypted ClientHello) |
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.br |
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.B ARES_SVCB_PARAM_IPV6HINT |
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- IPv6 address hints (RFC 9460 Section 7.3). Datatype: \fIARES_OPT_DATATYPE_INADDR6_LIST\fP |
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.br |
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.RE |
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.B ares_opt_param_t - |
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OPT RR known parameters as returned by \fIares_dns_opt_get_datatype(3)\fP |
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with \fIARES_RR_OPT_OPTIONS\fB: |
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.RS 4 |
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.B ARES_OPT_PARAM_LLQ |
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- RFC 8764. Apple's DNS Long-Lived Queries Protocol. Datatype: \fIARES_OPT_DATATYPE_BIN\fP |
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.br |
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.B ARES_OPT_PARAM_UL |
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- http://files.dns-sd.org/draft-sekar-dns-ul.txt: Update Lease. Datatype: \fIARES_OPT_DATATYPE_U32\fP |
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.br |
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.B ARES_OPT_PARAM_NSID |
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- RFC 5001. Name Server Identification. Datatype: \fIARES_OPT_DATATYPE_BIN\fP |
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.br |
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.B ARES_OPT_PARAM_DAU |
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- RFC 6975. DNSSEC Algorithm Understood. Datatype: \fIARES_OPT_DATATYPE_U8_LIST\fP |
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.br |
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.B ARES_OPT_PARAM_DHU |
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- RFC 6975. DS Hash Understood. Datatype: \fIARES_OPT_DATATYPE_U8_LIST\fP |
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.br |
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.B ARES_OPT_PARAM_N3U |
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- RFC 6975. NSEC3 Hash Understood. Datatype: \fIARES_OPT_DATATYPE_U8_LIST\fP |
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.br |
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.B ARES_OPT_PARAM_EDNS_CLIENT_SUBNET |
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- RFC 7871. Client Subnet. Datatype: \fIARES_OPT_DATATYPE_BIN\fP |
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.br |
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.B ARES_OPT_PARAM_EDNS_EXPIRE |
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- RFC 7314. Expire Timer. Datatype: \fIARES_OPT_DATATYPE_U32\fP |
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.br |
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.B ARES_OPT_PARAM_COOKIE |
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- RFC 7873. Client and Server Cookies. Datatype: \fIARES_OPT_DATATYPE_BIN\fP |
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.br |
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.B ARES_OPT_PARAM_EDNS_TCP_KEEPALIVE |
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- RFC 7828. TCP Keepalive timeout. Datatype: \fIARES_OPT_DATATYPE_U16\fP |
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.br |
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.B ARES_OPT_PARAM_PADDING |
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- RFC 7830. Padding. Datatype: \fIARES_OPT_DATATYPE_BIN\fP |
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.br |
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.B ARES_OPT_PARAM_CHAIN |
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- RFC 7901. Chain query requests. Datatype: \fIARES_OPT_DATATYPE_NAME\fP |
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.br |
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.B ARES_OPT_PARAM_EDNS_KEY_TAG |
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- RFC 8145. Signaling Trust Anchor Knowledge in DNSSEC. Datatype: \fIARES_OPT_DATATYPE_U16_LIST\fP |
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.br |
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.B ARES_OPT_PARAM_EXTENDED_DNS_ERROR |
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- RFC 8914. Extended ERROR code and message. Datatype: \fIARES_OPT_DATATYPE_BIN\fP |
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.br |
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.RE |
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.SH DESCRIPTION |
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The \fIares_dns_rec_type_tostr(3)\fP function outputs a human readable DNS record |
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type from its numeric form passed in |
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.IR type . |
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The \fIares_dns_class_tostr(3)\fP function outputs a human readable DNS class |
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from its numeric form passed in |
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.IR qclass . |
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The \fIares_dns_opcode_tostr(3)\fP function outputs a human readable DNS opcode |
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from its numeric form in |
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.IR opcode . |
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The \fIares_dns_rr_key_tostr(3)\fP function outputs a human readable DNS Resource |
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Record parameter name from its numeric form in |
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.IR key . |
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The \fIares_dns_section_tostr(3)\fP function outputs a human readable DNS |
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message section from its numeric form in |
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.IR section . |
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The \fIares_dns_rcode_tostr(3)\fP function outputs a human readable DNS |
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response code from its numeric form in |
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.IR rcode . |
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The \fIares_dns_class_fromstr(3)\fP function outputs the DNS class in numeric |
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from from its string representation in |
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.IR str . |
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The result is stored into the variable pointed to by |
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.IR qclass . |
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The \fIares_dns_rec_type_fromstr(3)\fP function outputs the DNS record type in |
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numeric from from its string representation in |
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.IR str . |
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The result is stored into the variable pointed to by |
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.IR qtype . |
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The \fIares_dns_rr_get_keys(3)\fP function retrieves a list of parameters that |
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may be set or retrieved for the provided |
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.IR type . |
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The count of returned keys is stored into the variable pointed to by |
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.IR cnt . |
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The \fIares_dns_rr_key_datatype(3)\fP function retrieves the associated datatype |
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for an RR parameter specified by |
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.IR key . |
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The \fIares_dns_rr_key_to_rec_type(3)\fP function dereferences the provided RR |
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parameter specified by |
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.IR key |
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to the DNS Record Type it belongs. |
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The \fIares_dns_opt_get_datatype(3)\fP function is used in association with |
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\fIares_dns_rr_set_opt(3)\fP and \fIares_dns_rr_get_opt(3)\fP to retrieve the |
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datatype of an option record contained within an RR as specified in |
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.IR key |
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if it is known. The raw option record identifier is provided by |
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.IR opt . |
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The \fIares_dns_opt_get_name(3)\fP function is used in association with |
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\fIares_dns_rr_set_opt(3)\fP and \fIares_dns_rr_get_opt(3)\fP to retrieve human |
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readable parameter name of an option record contained within an RR as specified |
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in |
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.IR key |
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if it is known. The raw option record identifier is provided by |
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.IR opt . |
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.SH RETURN VALUES |
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\fIares_dns_rec_type_tostr(3)\fP, \fIares_dns_class_tostr(3)\fP, |
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\fIares_dns_opcode_tostr(3)\fP, \fIares_dns_rr_key_tostr(3)\fP, |
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\fIares_dns_section_tostr(3)\fP, \fIares_dns_rcode_tostr(3)\fP, and |
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\fIares_dns_opt_get_name(3)\fP all return a human printable ASCII string, or |
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NULL on error. |
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\fIares_dns_class_fromstr(3)\fP and \fIares_dns_rec_type_fromstr(3)\fP return |
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.B ARES_TRUE |
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on successful conversion, otherwise |
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.B ARES_FALSE. |
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\fIares_dns_rr_get_keys(3)\fP returns an array of keys or NULL on failure. |
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\fIares_dns_rr_key_datatype(3)\fP, \fIares_dns_rr_key_to_rec_type(3)\fP, and |
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\fIares_dns_opt_get_datatype(3)\fP return their respective integer values, or |
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0 on failure. |
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.SH AVAILABILITY |
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These functions were first introduced in c-ares version 1.22.0. |
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.SH SEE ALSO |
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.BR ares_dns_record (3), |
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.BR ares_dns_rr (3), |
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.BR ares_init (3)
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