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/* SPDX-License-Identifier: GPL-2.0+ WITH Linux-syscall-note */
/* DNS resolver interface definitions.
*
* Copyright (C) 2018 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public Licence
* as published by the Free Software Foundation; either version
* 2 of the Licence, or (at your option) any later version.
*/
#ifndef _LINUX_DNS_RESOLVER_H
#define _LINUX_DNS_RESOLVER_H
#include <linux/types.h>
/*
* Type of payload.
*/
enum dns_payload_content_type {
DNS_PAYLOAD_IS_SERVER_LIST = 0, /* List of servers, requested by srv=1 */
};
/*
* Type of address that might be found in an address record.
*/
enum dns_payload_address_type {
DNS_ADDRESS_IS_IPV4 = 0, /* 4-byte AF_INET address */
DNS_ADDRESS_IS_IPV6 = 1, /* 16-byte AF_INET6 address */
};
/*
* Type of protocol used to access a server.
*/
enum dns_payload_protocol_type {
DNS_SERVER_PROTOCOL_UNSPECIFIED = 0,
DNS_SERVER_PROTOCOL_UDP = 1, /* Use UDP to talk to the server */
DNS_SERVER_PROTOCOL_TCP = 2, /* Use TCP to talk to the server */
};
/*
* Source of record included in DNS resolver payload.
*/
enum dns_record_source {
DNS_RECORD_UNAVAILABLE = 0, /* No source available (empty record) */
DNS_RECORD_FROM_CONFIG = 1, /* From local configuration data */
DNS_RECORD_FROM_DNS_A = 2, /* From DNS A or AAAA record */
DNS_RECORD_FROM_DNS_AFSDB = 3, /* From DNS AFSDB record */
DNS_RECORD_FROM_DNS_SRV = 4, /* From DNS SRV record */
DNS_RECORD_FROM_NSS = 5, /* From NSS */
NR__dns_record_source
};
/*
* Status of record included in DNS resolver payload.
*/
enum dns_lookup_status {
DNS_LOOKUP_NOT_DONE = 0, /* No lookup has been made */
DNS_LOOKUP_GOOD = 1, /* Good records obtained */
DNS_LOOKUP_GOOD_WITH_BAD = 2, /* Good records, some decoding errors */
DNS_LOOKUP_BAD = 3, /* Couldn't decode results */
DNS_LOOKUP_GOT_NOT_FOUND = 4, /* Got a "Not Found" result */
DNS_LOOKUP_GOT_LOCAL_FAILURE = 5, /* Local failure during lookup */
DNS_LOOKUP_GOT_TEMP_FAILURE = 6, /* Temporary failure during lookup */
DNS_LOOKUP_GOT_NS_FAILURE = 7, /* Name server failure */
NR__dns_lookup_status
};
/*
* Header at the beginning of binary format payload.
*/
struct dns_payload_header {
__u8 zero; /* Zero byte: marks this as not being text */
__u8 content; /* enum dns_payload_content_type */
__u8 version; /* Encoding version */
} __attribute__((packed));
/*
* Header at the beginning of a V1 server list. This is followed directly by
* the server records. Each server records begins with a struct of type
* dns_server_list_v1_server.
*/
struct dns_server_list_v1_header {
struct dns_payload_header hdr;
__u8 source; /* enum dns_record_source */
__u8 status; /* enum dns_lookup_status */
__u8 nr_servers; /* Number of server records following this */
} __attribute__((packed));
/*
* Header at the beginning of each V1 server record. This is followed by the
* characters of the name with no NUL-terminator, followed by the address
* records for that server. Each address record begins with a struct of type
* struct dns_server_list_v1_address.
*/
struct dns_server_list_v1_server {
__u16 name_len; /* Length of name (LE) */
__u16 priority; /* Priority (as SRV record) (LE) */
__u16 weight; /* Weight (as SRV record) (LE) */
__u16 port; /* UDP/TCP port number (LE) */
__u8 source; /* enum dns_record_source */
__u8 status; /* enum dns_lookup_status */
__u8 protocol; /* enum dns_payload_protocol_type */
__u8 nr_addrs;
} __attribute__((packed));
/*
* Header at the beginning of each V1 address record. This is followed by the
* bytes of the address, 4 for IPV4 and 16 for IPV6.
*/
struct dns_server_list_v1_address {
__u8 address_type; /* enum dns_payload_address_type */
} __attribute__((packed));
#endif /* _LINUX_DNS_RESOLVER_H */
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