183 lines
6.5 KiB
C
183 lines
6.5 KiB
C
/* SPDX-License-Identifier: LGPL-2.1-or-later */
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#pragma once
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#include "sd-event.h"
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#include "in-addr-util.h"
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typedef struct DnsTransaction DnsTransaction;
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typedef enum DnsTransactionState DnsTransactionState;
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typedef enum DnsTransactionSource DnsTransactionSource;
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#include "resolved-dns-answer.h"
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#include "resolved-dns-dnssec.h"
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#include "resolved-dns-packet.h"
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#include "resolved-dns-question.h"
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#include "resolved-dns-server.h"
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enum DnsTransactionState {
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DNS_TRANSACTION_NULL,
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DNS_TRANSACTION_PENDING,
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DNS_TRANSACTION_VALIDATING,
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DNS_TRANSACTION_RCODE_FAILURE,
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DNS_TRANSACTION_SUCCESS,
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DNS_TRANSACTION_NO_SERVERS,
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DNS_TRANSACTION_TIMEOUT,
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DNS_TRANSACTION_ATTEMPTS_MAX_REACHED,
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DNS_TRANSACTION_INVALID_REPLY,
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DNS_TRANSACTION_ERRNO,
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DNS_TRANSACTION_ABORTED,
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DNS_TRANSACTION_DNSSEC_FAILED,
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DNS_TRANSACTION_NO_TRUST_ANCHOR,
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DNS_TRANSACTION_RR_TYPE_UNSUPPORTED,
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DNS_TRANSACTION_NETWORK_DOWN,
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DNS_TRANSACTION_NOT_FOUND, /* like NXDOMAIN, but when LLMNR/TCP connections fail */
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_DNS_TRANSACTION_STATE_MAX,
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_DNS_TRANSACTION_STATE_INVALID = -1
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};
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#define DNS_TRANSACTION_IS_LIVE(state) IN_SET((state), DNS_TRANSACTION_NULL, DNS_TRANSACTION_PENDING, DNS_TRANSACTION_VALIDATING)
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enum DnsTransactionSource {
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DNS_TRANSACTION_NETWORK,
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DNS_TRANSACTION_CACHE,
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DNS_TRANSACTION_ZONE,
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DNS_TRANSACTION_TRUST_ANCHOR,
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_DNS_TRANSACTION_SOURCE_MAX,
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_DNS_TRANSACTION_SOURCE_INVALID = -1
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};
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struct DnsTransaction {
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DnsScope *scope;
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DnsResourceKey *key;
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DnsTransactionState state;
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uint16_t id;
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bool tried_stream:1;
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bool initial_jitter_scheduled:1;
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bool initial_jitter_elapsed:1;
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bool clamp_ttl:1;
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bool probing:1;
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DnsPacket *sent, *received;
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DnsAnswer *answer;
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int answer_rcode;
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DnssecResult answer_dnssec_result;
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DnsTransactionSource answer_source;
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uint32_t answer_nsec_ttl;
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int answer_errno; /* if state is DNS_TRANSACTION_ERRNO */
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/* Indicates whether the primary answer is authenticated,
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* i.e. whether the RRs from answer which directly match the
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* question are authenticated, or, if there are none, whether
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* the NODATA or NXDOMAIN case is. It says nothing about
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* additional RRs listed in the answer, however they have
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* their own DNS_ANSWER_AUTHORIZED FLAGS. Note that this bit
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* is defined different than the AD bit in DNS packets, as
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* that covers more than just the actual primary answer. */
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bool answer_authenticated;
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/* Contains DNSKEY, DS, SOA RRs we already verified and need
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* to authenticate this reply */
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DnsAnswer *validated_keys;
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usec_t start_usec;
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usec_t next_attempt_after;
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sd_event_source *timeout_event_source;
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unsigned n_attempts;
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unsigned n_picked_servers;
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/* UDP connection logic, if we need it */
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int dns_udp_fd;
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sd_event_source *dns_udp_event_source;
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/* TCP connection logic, if we need it */
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DnsStream *stream;
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/* The active server */
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DnsServer *server;
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/* The features of the DNS server at time of transaction start */
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DnsServerFeatureLevel current_feature_level;
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/* If we got SERVFAIL back, we retry the lookup, using a lower feature level than we used before. */
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DnsServerFeatureLevel clamp_feature_level;
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/* Query candidates this transaction is referenced by and that
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* shall be notified about this specific transaction
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* completing. */
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Set *notify_query_candidates, *notify_query_candidates_done;
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/* Zone items this transaction is referenced by and that shall
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* be notified about completion. */
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Set *notify_zone_items, *notify_zone_items_done;
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/* Other transactions that this transactions is referenced by
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* and that shall be notified about completion. This is used
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* when transactions want to validate their RRsets, but need
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* another DNSKEY or DS RR to do so. */
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Set *notify_transactions, *notify_transactions_done;
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/* The opposite direction: the transactions this transaction
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* created in order to request DNSKEY or DS RRs. */
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Set *dnssec_transactions;
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unsigned block_gc;
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LIST_FIELDS(DnsTransaction, transactions_by_scope);
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LIST_FIELDS(DnsTransaction, transactions_by_stream);
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};
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int dns_transaction_new(DnsTransaction **ret, DnsScope *s, DnsResourceKey *key);
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DnsTransaction* dns_transaction_free(DnsTransaction *t);
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bool dns_transaction_gc(DnsTransaction *t);
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DEFINE_TRIVIAL_CLEANUP_FUNC(DnsTransaction*, dns_transaction_gc);
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int dns_transaction_go(DnsTransaction *t);
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void dns_transaction_process_reply(DnsTransaction *t, DnsPacket *p);
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void dns_transaction_complete(DnsTransaction *t, DnsTransactionState state);
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void dns_transaction_notify(DnsTransaction *t, DnsTransaction *source);
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int dns_transaction_validate_dnssec(DnsTransaction *t);
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int dns_transaction_request_dnssec_keys(DnsTransaction *t);
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const char* dns_transaction_state_to_string(DnsTransactionState p) _const_;
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DnsTransactionState dns_transaction_state_from_string(const char *s) _pure_;
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const char* dns_transaction_source_to_string(DnsTransactionSource p) _const_;
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DnsTransactionSource dns_transaction_source_from_string(const char *s) _pure_;
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/* LLMNR Jitter interval, see RFC 4795 Section 7 */
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#define LLMNR_JITTER_INTERVAL_USEC (100 * USEC_PER_MSEC)
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/* mDNS Jitter interval, see RFC 6762 Section 5.2 */
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#define MDNS_JITTER_MIN_USEC (20 * USEC_PER_MSEC)
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#define MDNS_JITTER_RANGE_USEC (100 * USEC_PER_MSEC)
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/* mDNS probing interval, see RFC 6762 Section 8.1 */
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#define MDNS_PROBING_INTERVAL_USEC (250 * USEC_PER_MSEC)
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/* Maximum attempts to send DNS requests, across all DNS servers */
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#define DNS_TRANSACTION_ATTEMPTS_MAX 24
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/* Maximum attempts to send LLMNR requests, see RFC 4795 Section 2.7 */
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#define LLMNR_TRANSACTION_ATTEMPTS_MAX 3
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/* Maximum attempts to send MDNS requests, see RFC 6762 Section 8.1 */
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#define MDNS_TRANSACTION_ATTEMPTS_MAX 3
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#define TRANSACTION_ATTEMPTS_MAX(p) (((p) == DNS_PROTOCOL_LLMNR) ? \
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LLMNR_TRANSACTION_ATTEMPTS_MAX : \
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(((p) == DNS_PROTOCOL_MDNS) ? \
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MDNS_TRANSACTION_ATTEMPTS_MAX : \
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DNS_TRANSACTION_ATTEMPTS_MAX))
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