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#pragma once
/***
This file is part of systemd.
Copyright 2014 Lennart Poettering
systemd is free software; you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.
systemd is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/
typedef struct DnsTransaction DnsTransaction;
typedef enum DnsTransactionState DnsTransactionState;
typedef enum DnsTransactionSource DnsTransactionSource;
enum DnsTransactionState {
DNS_TRANSACTION_NULL,
DNS_TRANSACTION_PENDING,
DNS_TRANSACTION_VALIDATING,
DNS_TRANSACTION_RCODE_FAILURE,
DNS_TRANSACTION_SUCCESS,
DNS_TRANSACTION_NO_SERVERS,
DNS_TRANSACTION_TIMEOUT,
DNS_TRANSACTION_ATTEMPTS_MAX_REACHED,
DNS_TRANSACTION_INVALID_REPLY,
DNS_TRANSACTION_ERRNO,
DNS_TRANSACTION_ABORTED,
DNS_TRANSACTION_DNSSEC_FAILED,
DNS_TRANSACTION_NO_TRUST_ANCHOR,
DNS_TRANSACTION_RR_TYPE_UNSUPPORTED,
DNS_TRANSACTION_NETWORK_DOWN,
DNS_TRANSACTION_NOT_FOUND, /* like NXDOMAIN, but when LLMNR/TCP connections fail */
_DNS_TRANSACTION_STATE_MAX,
_DNS_TRANSACTION_STATE_INVALID = -1
};
#define DNS_TRANSACTION_IS_LIVE(state) IN_SET((state), DNS_TRANSACTION_NULL, DNS_TRANSACTION_PENDING, DNS_TRANSACTION_VALIDATING)
enum DnsTransactionSource {
DNS_TRANSACTION_NETWORK,
DNS_TRANSACTION_CACHE,
DNS_TRANSACTION_ZONE,
DNS_TRANSACTION_TRUST_ANCHOR,
_DNS_TRANSACTION_SOURCE_MAX,
_DNS_TRANSACTION_SOURCE_INVALID = -1
};
#include "resolved-dns-answer.h"
#include "resolved-dns-packet.h"
#include "resolved-dns-question.h"
#include "resolved-dns-scope.h"
#include "resolved-dns-server.h"
#include "resolved-dns-stream.h"
struct DnsTransaction {
DnsScope *scope;
DnsResourceKey *key;
DnsTransactionState state;
uint16_t id;
bool tried_stream:1;
bool initial_jitter_scheduled:1;
bool initial_jitter_elapsed:1;
bool clamp_ttl:1;
bool probing:1;
DnsPacket *sent, *received;
DnsAnswer *answer;
int answer_rcode;
DnssecResult answer_dnssec_result;
DnsTransactionSource answer_source;
uint32_t answer_nsec_ttl;
int answer_errno; /* if state is DNS_TRANSACTION_ERRNO */
/* Indicates whether the primary answer is authenticated,
* i.e. whether the RRs from answer which directly match the
* question are authenticated, or, if there are none, whether
* the NODATA or NXDOMAIN case is. It says nothing about
* additional RRs listed in the answer, however they have
* their own DNS_ANSWER_AUTHORIZED FLAGS. Note that this bit
* is defined different than the AD bit in DNS packets, as
* that covers more than just the actual primary answer. */
bool answer_authenticated;
/* Contains DNSKEY, DS, SOA RRs we already verified and need
* to authenticate this reply */
DnsAnswer *validated_keys;
usec_t start_usec;
usec_t next_attempt_after;
sd_event_source *timeout_event_source;
unsigned n_attempts;
/* UDP connection logic, if we need it */
int dns_udp_fd;
sd_event_source *dns_udp_event_source;
/* TCP connection logic, if we need it */
DnsStream *stream;
/* The active server */
DnsServer *server;
/* The features of the DNS server at time of transaction start */
DnsServerFeatureLevel current_feature_level;
/* If we got SERVFAIL back, we retry the lookup, using a lower feature level than we used before. */
DnsServerFeatureLevel clamp_feature_level;
/* Query candidates this transaction is referenced by and that
* shall be notified about this specific transaction
* completing. */
Set *notify_query_candidates, *notify_query_candidates_done;
/* Zone items this transaction is referenced by and that shall
* be notified about completion. */
Set *notify_zone_items, *notify_zone_items_done;
/* Other transactions that this transactions is referenced by
* and that shall be notified about completion. This is used
* when transactions want to validate their RRsets, but need
* another DNSKEY or DS RR to do so. */
Set *notify_transactions, *notify_transactions_done;
/* The opposite direction: the transactions this transaction
* created in order to request DNSKEY or DS RRs. */
Set *dnssec_transactions;
unsigned block_gc;
LIST_FIELDS(DnsTransaction, transactions_by_scope);
};
int dns_transaction_new(DnsTransaction **ret, DnsScope *s, DnsResourceKey *key);
DnsTransaction* dns_transaction_free(DnsTransaction *t);
bool dns_transaction_gc(DnsTransaction *t);
int dns_transaction_go(DnsTransaction *t);
void dns_transaction_process_reply(DnsTransaction *t, DnsPacket *p);
void dns_transaction_complete(DnsTransaction *t, DnsTransactionState state);
void dns_transaction_notify(DnsTransaction *t, DnsTransaction *source);
int dns_transaction_validate_dnssec(DnsTransaction *t);
int dns_transaction_request_dnssec_keys(DnsTransaction *t);
const char* dns_transaction_state_to_string(DnsTransactionState p) _const_;
DnsTransactionState dns_transaction_state_from_string(const char *s) _pure_;
const char* dns_transaction_source_to_string(DnsTransactionSource p) _const_;
DnsTransactionSource dns_transaction_source_from_string(const char *s) _pure_;
/* LLMNR Jitter interval, see RFC 4795 Section 7 */
#define LLMNR_JITTER_INTERVAL_USEC (100 * USEC_PER_MSEC)
/* mDNS Jitter interval, see RFC 6762 Section 5.2 */
#define MDNS_JITTER_MIN_USEC (20 * USEC_PER_MSEC)
#define MDNS_JITTER_RANGE_USEC (100 * USEC_PER_MSEC)
/* mDNS probing interval, see RFC 6762 Section 8.1 */
#define MDNS_PROBING_INTERVAL_USEC (250 * USEC_PER_MSEC)
/* Maximum attempts to send DNS requests, across all DNS servers */
#define DNS_TRANSACTION_ATTEMPTS_MAX 24
/* Maximum attempts to send LLMNR requests, see RFC 4795 Section 2.7 */
#define LLMNR_TRANSACTION_ATTEMPTS_MAX 3
/* Maximum attempts to send MDNS requests, see RFC 6762 Section 8.1 */
#define MDNS_TRANSACTION_ATTEMPTS_MAX 3
#define TRANSACTION_ATTEMPTS_MAX(p) (((p) == DNS_PROTOCOL_LLMNR) ? \
LLMNR_TRANSACTION_ATTEMPTS_MAX : \
(((p) == DNS_PROTOCOL_MDNS) ? \
MDNS_TRANSACTION_ATTEMPTS_MAX : \
DNS_TRANSACTION_ATTEMPTS_MAX))
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