1 /* SPDX-License-Identifier: LGPL-2.1+ */
5 This file is part of systemd.
7 Copyright 2014 Lennart Poettering
9 systemd is free software; you can redistribute it and/or modify it
10 under the terms of the GNU Lesser General Public License as published by
11 the Free Software Foundation; either version 2.1 of the License, or
12 (at your option) any later version.
14 systemd is distributed in the hope that it will be useful, but
15 WITHOUT ANY WARRANTY; without even the implied warranty of
16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
17 Lesser General Public License for more details.
19 You should have received a copy of the GNU Lesser General Public License
20 along with systemd; If not, see <http://www.gnu.org/licenses/>.
23 typedef struct DnsTransaction DnsTransaction
;
24 typedef enum DnsTransactionState DnsTransactionState
;
25 typedef enum DnsTransactionSource DnsTransactionSource
;
27 enum DnsTransactionState
{
29 DNS_TRANSACTION_PENDING
,
30 DNS_TRANSACTION_VALIDATING
,
31 DNS_TRANSACTION_RCODE_FAILURE
,
32 DNS_TRANSACTION_SUCCESS
,
33 DNS_TRANSACTION_NO_SERVERS
,
34 DNS_TRANSACTION_TIMEOUT
,
35 DNS_TRANSACTION_ATTEMPTS_MAX_REACHED
,
36 DNS_TRANSACTION_INVALID_REPLY
,
37 DNS_TRANSACTION_ERRNO
,
38 DNS_TRANSACTION_ABORTED
,
39 DNS_TRANSACTION_DNSSEC_FAILED
,
40 DNS_TRANSACTION_NO_TRUST_ANCHOR
,
41 DNS_TRANSACTION_RR_TYPE_UNSUPPORTED
,
42 DNS_TRANSACTION_NETWORK_DOWN
,
43 DNS_TRANSACTION_NOT_FOUND
, /* like NXDOMAIN, but when LLMNR/TCP connections fail */
44 _DNS_TRANSACTION_STATE_MAX
,
45 _DNS_TRANSACTION_STATE_INVALID
= -1
48 #define DNS_TRANSACTION_IS_LIVE(state) IN_SET((state), DNS_TRANSACTION_NULL, DNS_TRANSACTION_PENDING, DNS_TRANSACTION_VALIDATING)
50 enum DnsTransactionSource
{
51 DNS_TRANSACTION_NETWORK
,
52 DNS_TRANSACTION_CACHE
,
54 DNS_TRANSACTION_TRUST_ANCHOR
,
55 _DNS_TRANSACTION_SOURCE_MAX
,
56 _DNS_TRANSACTION_SOURCE_INVALID
= -1
59 #include "resolved-dns-answer.h"
60 #include "resolved-dns-packet.h"
61 #include "resolved-dns-question.h"
62 #include "resolved-dns-scope.h"
63 #include "resolved-dns-server.h"
64 #include "resolved-dns-stream.h"
66 struct DnsTransaction
{
71 DnsTransactionState state
;
77 bool initial_jitter_scheduled
:1;
78 bool initial_jitter_elapsed
:1;
84 DnsPacket
*sent
, *received
;
88 DnssecResult answer_dnssec_result
;
89 DnsTransactionSource answer_source
;
90 uint32_t answer_nsec_ttl
;
91 int answer_errno
; /* if state is DNS_TRANSACTION_ERRNO */
93 /* Indicates whether the primary answer is authenticated,
94 * i.e. whether the RRs from answer which directly match the
95 * question are authenticated, or, if there are none, whether
96 * the NODATA or NXDOMAIN case is. It says nothing about
97 * additional RRs listed in the answer, however they have
98 * their own DNS_ANSWER_AUTHORIZED FLAGS. Note that this bit
99 * is defined different than the AD bit in DNS packets, as
100 * that covers more than just the actual primary answer. */
101 bool answer_authenticated
;
103 /* Contains DNSKEY, DS, SOA RRs we already verified and need
104 * to authenticate this reply */
105 DnsAnswer
*validated_keys
;
108 usec_t next_attempt_after
;
109 sd_event_source
*timeout_event_source
;
112 unsigned n_picked_servers
;
114 /* UDP connection logic, if we need it */
116 sd_event_source
*dns_udp_event_source
;
118 /* TCP connection logic, if we need it */
121 /* The active server */
124 /* The features of the DNS server at time of transaction start */
125 DnsServerFeatureLevel current_feature_level
;
127 /* If we got SERVFAIL back, we retry the lookup, using a lower feature level than we used before. */
128 DnsServerFeatureLevel clamp_feature_level
;
130 /* Query candidates this transaction is referenced by and that
131 * shall be notified about this specific transaction
133 Set
*notify_query_candidates
, *notify_query_candidates_done
;
135 /* Zone items this transaction is referenced by and that shall
136 * be notified about completion. */
137 Set
*notify_zone_items
, *notify_zone_items_done
;
139 /* Other transactions that this transactions is referenced by
140 * and that shall be notified about completion. This is used
141 * when transactions want to validate their RRsets, but need
142 * another DNSKEY or DS RR to do so. */
143 Set
*notify_transactions
, *notify_transactions_done
;
145 /* The opposite direction: the transactions this transaction
146 * created in order to request DNSKEY or DS RRs. */
147 Set
*dnssec_transactions
;
151 LIST_FIELDS(DnsTransaction
, transactions_by_scope
);
154 int dns_transaction_new(DnsTransaction
**ret
, DnsScope
*s
, DnsResourceKey
*key
);
155 DnsTransaction
* dns_transaction_free(DnsTransaction
*t
);
157 bool dns_transaction_gc(DnsTransaction
*t
);
158 int dns_transaction_go(DnsTransaction
*t
);
160 void dns_transaction_process_reply(DnsTransaction
*t
, DnsPacket
*p
);
161 void dns_transaction_complete(DnsTransaction
*t
, DnsTransactionState state
);
163 void dns_transaction_notify(DnsTransaction
*t
, DnsTransaction
*source
);
164 int dns_transaction_validate_dnssec(DnsTransaction
*t
);
165 int dns_transaction_request_dnssec_keys(DnsTransaction
*t
);
167 const char* dns_transaction_state_to_string(DnsTransactionState p
) _const_
;
168 DnsTransactionState
dns_transaction_state_from_string(const char *s
) _pure_
;
170 const char* dns_transaction_source_to_string(DnsTransactionSource p
) _const_
;
171 DnsTransactionSource
dns_transaction_source_from_string(const char *s
) _pure_
;
173 /* LLMNR Jitter interval, see RFC 4795 Section 7 */
174 #define LLMNR_JITTER_INTERVAL_USEC (100 * USEC_PER_MSEC)
176 /* mDNS Jitter interval, see RFC 6762 Section 5.2 */
177 #define MDNS_JITTER_MIN_USEC (20 * USEC_PER_MSEC)
178 #define MDNS_JITTER_RANGE_USEC (100 * USEC_PER_MSEC)
180 /* mDNS probing interval, see RFC 6762 Section 8.1 */
181 #define MDNS_PROBING_INTERVAL_USEC (250 * USEC_PER_MSEC)
183 /* Maximum attempts to send DNS requests, across all DNS servers */
184 #define DNS_TRANSACTION_ATTEMPTS_MAX 24
186 /* Maximum attempts to send LLMNR requests, see RFC 4795 Section 2.7 */
187 #define LLMNR_TRANSACTION_ATTEMPTS_MAX 3
189 /* Maximum attempts to send MDNS requests, see RFC 6762 Section 8.1 */
190 #define MDNS_TRANSACTION_ATTEMPTS_MAX 3
192 #define TRANSACTION_ATTEMPTS_MAX(p) (((p) == DNS_PROTOCOL_LLMNR) ? \
193 LLMNR_TRANSACTION_ATTEMPTS_MAX : \
194 (((p) == DNS_PROTOCOL_MDNS) ? \
195 MDNS_TRANSACTION_ATTEMPTS_MAX : \
196 DNS_TRANSACTION_ATTEMPTS_MAX))