117 lines · c
1/* SPDX-License-Identifier: GPL-2.0+ WITH Linux-syscall-note */2/* DNS resolver interface definitions.3 *4 * Copyright (C) 2018 Red Hat, Inc. All Rights Reserved.5 * Written by David Howells (dhowells@redhat.com)6 *7 * This program is free software; you can redistribute it and/or8 * modify it under the terms of the GNU General Public Licence9 * as published by the Free Software Foundation; either version10 * 2 of the Licence, or (at your option) any later version.11 */12 13#ifndef _UAPI_LINUX_DNS_RESOLVER_H14#define _UAPI_LINUX_DNS_RESOLVER_H15 16#include <linux/types.h>17 18/*19 * Type of payload.20 */21enum dns_payload_content_type {22 DNS_PAYLOAD_IS_SERVER_LIST = 0, /* List of servers, requested by srv=1 */23};24 25/*26 * Type of address that might be found in an address record.27 */28enum dns_payload_address_type {29 DNS_ADDRESS_IS_IPV4 = 0, /* 4-byte AF_INET address */30 DNS_ADDRESS_IS_IPV6 = 1, /* 16-byte AF_INET6 address */31};32 33/*34 * Type of protocol used to access a server.35 */36enum dns_payload_protocol_type {37 DNS_SERVER_PROTOCOL_UNSPECIFIED = 0,38 DNS_SERVER_PROTOCOL_UDP = 1, /* Use UDP to talk to the server */39 DNS_SERVER_PROTOCOL_TCP = 2, /* Use TCP to talk to the server */40};41 42/*43 * Source of record included in DNS resolver payload.44 */45enum dns_record_source {46 DNS_RECORD_UNAVAILABLE = 0, /* No source available (empty record) */47 DNS_RECORD_FROM_CONFIG = 1, /* From local configuration data */48 DNS_RECORD_FROM_DNS_A = 2, /* From DNS A or AAAA record */49 DNS_RECORD_FROM_DNS_AFSDB = 3, /* From DNS AFSDB record */50 DNS_RECORD_FROM_DNS_SRV = 4, /* From DNS SRV record */51 DNS_RECORD_FROM_NSS = 5, /* From NSS */52 NR__dns_record_source53};54 55/*56 * Status of record included in DNS resolver payload.57 */58enum dns_lookup_status {59 DNS_LOOKUP_NOT_DONE = 0, /* No lookup has been made */60 DNS_LOOKUP_GOOD = 1, /* Good records obtained */61 DNS_LOOKUP_GOOD_WITH_BAD = 2, /* Good records, some decoding errors */62 DNS_LOOKUP_BAD = 3, /* Couldn't decode results */63 DNS_LOOKUP_GOT_NOT_FOUND = 4, /* Got a "Not Found" result */64 DNS_LOOKUP_GOT_LOCAL_FAILURE = 5, /* Local failure during lookup */65 DNS_LOOKUP_GOT_TEMP_FAILURE = 6, /* Temporary failure during lookup */66 DNS_LOOKUP_GOT_NS_FAILURE = 7, /* Name server failure */67 NR__dns_lookup_status68};69 70/*71 * Header at the beginning of binary format payload.72 */73struct dns_payload_header {74 __u8 zero; /* Zero byte: marks this as not being text */75 __u8 content; /* enum dns_payload_content_type */76 __u8 version; /* Encoding version */77} __packed;78 79/*80 * Header at the beginning of a V1 server list. This is followed directly by81 * the server records. Each server records begins with a struct of type82 * dns_server_list_v1_server.83 */84struct dns_server_list_v1_header {85 struct dns_payload_header hdr;86 __u8 source; /* enum dns_record_source */87 __u8 status; /* enum dns_lookup_status */88 __u8 nr_servers; /* Number of server records following this */89} __packed;90 91/*92 * Header at the beginning of each V1 server record. This is followed by the93 * characters of the name with no NUL-terminator, followed by the address94 * records for that server. Each address record begins with a struct of type95 * struct dns_server_list_v1_address.96 */97struct dns_server_list_v1_server {98 __u16 name_len; /* Length of name (LE) */99 __u16 priority; /* Priority (as SRV record) (LE) */100 __u16 weight; /* Weight (as SRV record) (LE) */101 __u16 port; /* UDP/TCP port number (LE) */102 __u8 source; /* enum dns_record_source */103 __u8 status; /* enum dns_lookup_status */104 __u8 protocol; /* enum dns_payload_protocol_type */105 __u8 nr_addrs;106} __packed;107 108/*109 * Header at the beginning of each V1 address record. This is followed by the110 * bytes of the address, 4 for IPV4 and 16 for IPV6.111 */112struct dns_server_list_v1_address {113 __u8 address_type; /* enum dns_payload_address_type */114} __packed;115 116#endif /* _UAPI_LINUX_DNS_RESOLVER_H */117