35aa04e9ed
When a transaction is complete, and we notify its owners, make sure we deal correctly with the requesters removing themselves from the list of owners while we continue iterating. This was previously already dealt with with transactions that require other transactions for DNSSEC purposes, fix this for other possibly transaction owners too now. Since iterating through "Set" objects is not safe regarding removal of entries from it, rework the logic to use two Sets, and move each entry we notified from one set to the other set before we dispatch the notification. This move operation requires no additional memory, and enables us to ensure that we don't notify any object twice. Fixes: #2676
175 lines
6.3 KiB
C
175 lines
6.3 KiB
C
#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_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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#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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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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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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/* 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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/* 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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};
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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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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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/* 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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