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