cbe4216dd1
On LLMNR we never want to retry stream connections (since local TCP connections should work, and we don't want to unnecessarily delay operation), explicitly remember whether we already tried one, instead of deriving this from a still stored stream object. This way, we can free the stream early, without forgetting that we tried it.
174 lines
6 KiB
C
174 lines
6 KiB
C
/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
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#pragma once
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/***
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This file is part of systemd.
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Copyright 2014 Lennart Poettering
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systemd is free software; you can redistribute it and/or modify it
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under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation; either version 2.1 of the License, or
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(at your option) any later version.
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systemd is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with systemd; If not, see <http://www.gnu.org/licenses/>.
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***/
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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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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_RESOURCES,
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DNS_TRANSACTION_CONNECTION_FAILURE,
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DNS_TRANSACTION_ABORTED,
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DNS_TRANSACTION_DNSSEC_FAILED,
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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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#include "resolved-dns-answer.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-scope.h"
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struct DnsTransaction {
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DnsScope *scope;
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DnsResourceKey *key;
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char *key_string;
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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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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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/* 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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int dns_udp_fd;
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sd_event_source *dns_udp_event_source;
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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_features;
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/* TCP connection logic, if we need it */
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DnsStream *stream;
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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;
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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;
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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;
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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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};
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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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void dns_transaction_gc(DnsTransaction *t);
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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_key_string(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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/* Maximum attempts to send DNS requests, across all DNS servers */
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#define DNS_TRANSACTION_ATTEMPTS_MAX 16
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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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#define TRANSACTION_ATTEMPTS_MAX(p) ((p) == DNS_PROTOCOL_LLMNR ? LLMNR_TRANSACTION_ATTEMPTS_MAX : DNS_TRANSACTION_ATTEMPTS_MAX)
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