1 /* SPDX-License-Identifier: LGPL-2.1+ */
3 This file is part of systemd.
5 Copyright 2014 Lennart Poettering
7 systemd is free software; you can redistribute it and/or modify it
8 under the terms of the GNU Lesser General Public License as published by
9 the Free Software Foundation; either version 2.1 of the License, or
10 (at your option) any later version.
12 systemd is distributed in the hope that it will be useful, but
13 WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 Lesser General Public License for more details.
17 You should have received a copy of the GNU Lesser General Public License
18 along with systemd; If not, see <http://www.gnu.org/licenses/>.
21 #include "sd-messages.h"
24 #include "alloc-util.h"
25 #include "dns-domain.h"
26 #include "errno-list.h"
28 #include "random-util.h"
29 #include "resolved-dns-cache.h"
30 #include "resolved-dns-transaction.h"
31 #include "resolved-llmnr.h"
32 #include "string-table.h"
34 #define TRANSACTIONS_MAX 4096
35 #define TRANSACTION_TCP_TIMEOUT_USEC (10U*USEC_PER_SEC)
37 static void dns_transaction_reset_answer(DnsTransaction
*t
) {
40 t
->received
= dns_packet_unref(t
->received
);
41 t
->answer
= dns_answer_unref(t
->answer
);
43 t
->answer_dnssec_result
= _DNSSEC_RESULT_INVALID
;
44 t
->answer_source
= _DNS_TRANSACTION_SOURCE_INVALID
;
45 t
->answer_authenticated
= false;
46 t
->answer_nsec_ttl
= (uint32_t) -1;
50 static void dns_transaction_flush_dnssec_transactions(DnsTransaction
*t
) {
55 while ((z
= set_steal_first(t
->dnssec_transactions
))) {
56 set_remove(z
->notify_transactions
, t
);
57 set_remove(z
->notify_transactions_done
, t
);
58 dns_transaction_gc(z
);
62 static void dns_transaction_close_connection(DnsTransaction
*t
) {
66 /* Let's detach the stream from our transaction, in case something else keeps a reference to it. */
67 t
->stream
->complete
= NULL
;
68 t
->stream
->on_packet
= NULL
;
69 t
->stream
->transaction
= NULL
;
70 t
->stream
= dns_stream_unref(t
->stream
);
73 t
->dns_udp_event_source
= sd_event_source_unref(t
->dns_udp_event_source
);
74 t
->dns_udp_fd
= safe_close(t
->dns_udp_fd
);
77 static void dns_transaction_stop_timeout(DnsTransaction
*t
) {
80 t
->timeout_event_source
= sd_event_source_unref(t
->timeout_event_source
);
83 DnsTransaction
* dns_transaction_free(DnsTransaction
*t
) {
91 log_debug("Freeing transaction %" PRIu16
".", t
->id
);
93 dns_transaction_close_connection(t
);
94 dns_transaction_stop_timeout(t
);
96 dns_packet_unref(t
->sent
);
97 dns_transaction_reset_answer(t
);
99 dns_server_unref(t
->server
);
102 hashmap_remove_value(t
->scope
->transactions_by_key
, t
->key
, t
);
103 LIST_REMOVE(transactions_by_scope
, t
->scope
->transactions
, t
);
106 hashmap_remove(t
->scope
->manager
->dns_transactions
, UINT_TO_PTR(t
->id
));
109 while ((c
= set_steal_first(t
->notify_query_candidates
)))
110 set_remove(c
->transactions
, t
);
111 set_free(t
->notify_query_candidates
);
113 while ((c
= set_steal_first(t
->notify_query_candidates_done
)))
114 set_remove(c
->transactions
, t
);
115 set_free(t
->notify_query_candidates_done
);
117 while ((i
= set_steal_first(t
->notify_zone_items
)))
118 i
->probe_transaction
= NULL
;
119 set_free(t
->notify_zone_items
);
121 while ((i
= set_steal_first(t
->notify_zone_items_done
)))
122 i
->probe_transaction
= NULL
;
123 set_free(t
->notify_zone_items_done
);
125 while ((z
= set_steal_first(t
->notify_transactions
)))
126 set_remove(z
->dnssec_transactions
, t
);
127 set_free(t
->notify_transactions
);
129 while ((z
= set_steal_first(t
->notify_transactions_done
)))
130 set_remove(z
->dnssec_transactions
, t
);
131 set_free(t
->notify_transactions_done
);
133 dns_transaction_flush_dnssec_transactions(t
);
134 set_free(t
->dnssec_transactions
);
136 dns_answer_unref(t
->validated_keys
);
137 dns_resource_key_unref(t
->key
);
142 DEFINE_TRIVIAL_CLEANUP_FUNC(DnsTransaction
*, dns_transaction_free
);
144 bool dns_transaction_gc(DnsTransaction
*t
) {
150 if (set_isempty(t
->notify_query_candidates
) &&
151 set_isempty(t
->notify_query_candidates_done
) &&
152 set_isempty(t
->notify_zone_items
) &&
153 set_isempty(t
->notify_zone_items_done
) &&
154 set_isempty(t
->notify_transactions
) &&
155 set_isempty(t
->notify_transactions_done
)) {
156 dns_transaction_free(t
);
163 static uint16_t pick_new_id(Manager
*m
) {
166 /* Find a fresh, unused transaction id. Note that this loop is bounded because there's a limit on the number of
167 * transactions, and it's much lower than the space of IDs. */
169 assert_cc(TRANSACTIONS_MAX
< 0xFFFF);
172 random_bytes(&new_id
, sizeof(new_id
));
173 while (new_id
== 0 ||
174 hashmap_get(m
->dns_transactions
, UINT_TO_PTR(new_id
)));
179 int dns_transaction_new(DnsTransaction
**ret
, DnsScope
*s
, DnsResourceKey
*key
) {
180 _cleanup_(dns_transaction_freep
) DnsTransaction
*t
= NULL
;
187 /* Don't allow looking up invalid or pseudo RRs */
188 if (!dns_type_is_valid_query(key
->type
))
190 if (dns_type_is_obsolete(key
->type
))
193 /* We only support the IN class */
194 if (!IN_SET(key
->class, DNS_CLASS_IN
, DNS_CLASS_ANY
))
197 if (hashmap_size(s
->manager
->dns_transactions
) >= TRANSACTIONS_MAX
)
200 r
= hashmap_ensure_allocated(&s
->manager
->dns_transactions
, NULL
);
204 r
= hashmap_ensure_allocated(&s
->transactions_by_key
, &dns_resource_key_hash_ops
);
208 t
= new0(DnsTransaction
, 1);
213 t
->answer_source
= _DNS_TRANSACTION_SOURCE_INVALID
;
214 t
->answer_dnssec_result
= _DNSSEC_RESULT_INVALID
;
215 t
->answer_nsec_ttl
= (uint32_t) -1;
216 t
->key
= dns_resource_key_ref(key
);
217 t
->current_feature_level
= _DNS_SERVER_FEATURE_LEVEL_INVALID
;
218 t
->clamp_feature_level
= _DNS_SERVER_FEATURE_LEVEL_INVALID
;
220 t
->id
= pick_new_id(s
->manager
);
222 r
= hashmap_put(s
->manager
->dns_transactions
, UINT_TO_PTR(t
->id
), t
);
228 r
= hashmap_replace(s
->transactions_by_key
, t
->key
, t
);
230 hashmap_remove(s
->manager
->dns_transactions
, UINT_TO_PTR(t
->id
));
234 LIST_PREPEND(transactions_by_scope
, s
->transactions
, t
);
237 s
->manager
->n_transactions_total
++;
247 static void dns_transaction_shuffle_id(DnsTransaction
*t
) {
251 /* Pick a new ID for this transaction. */
253 new_id
= pick_new_id(t
->scope
->manager
);
254 assert_se(hashmap_remove_and_put(t
->scope
->manager
->dns_transactions
, UINT_TO_PTR(t
->id
), UINT_TO_PTR(new_id
), t
) >= 0);
256 log_debug("Transaction %" PRIu16
" is now %" PRIu16
".", t
->id
, new_id
);
259 /* Make sure we generate a new packet with the new ID */
260 t
->sent
= dns_packet_unref(t
->sent
);
263 static void dns_transaction_tentative(DnsTransaction
*t
, DnsPacket
*p
) {
264 _cleanup_free_
char *pretty
= NULL
;
265 char key_str
[DNS_RESOURCE_KEY_STRING_MAX
];
271 if (manager_our_packet(t
->scope
->manager
, p
) != 0)
274 (void) in_addr_to_string(p
->family
, &p
->sender
, &pretty
);
276 log_debug("Transaction %" PRIu16
" for <%s> on scope %s on %s/%s got tentative packet from %s.",
278 dns_resource_key_to_string(t
->key
, key_str
, sizeof key_str
),
279 dns_protocol_to_string(t
->scope
->protocol
),
280 t
->scope
->link
? t
->scope
->link
->name
: "*",
281 af_to_name_short(t
->scope
->family
),
284 /* RFC 4795, Section 4.1 says that the peer with the
285 * lexicographically smaller IP address loses */
286 if (memcmp(&p
->sender
, &p
->destination
, FAMILY_ADDRESS_SIZE(p
->family
)) >= 0) {
287 log_debug("Peer has lexicographically larger IP address and thus lost in the conflict.");
291 log_debug("We have the lexicographically larger IP address and thus lost in the conflict.");
295 while ((z
= set_first(t
->notify_zone_items
))) {
296 /* First, make sure the zone item drops the reference
298 dns_zone_item_probe_stop(z
);
300 /* Secondly, report this as conflict, so that we might
301 * look for a different hostname */
302 dns_zone_item_conflict(z
);
306 dns_transaction_gc(t
);
309 void dns_transaction_complete(DnsTransaction
*t
, DnsTransactionState state
) {
310 DnsQueryCandidate
*c
;
314 char key_str
[DNS_RESOURCE_KEY_STRING_MAX
];
317 assert(!DNS_TRANSACTION_IS_LIVE(state
));
319 if (state
== DNS_TRANSACTION_DNSSEC_FAILED
) {
320 dns_resource_key_to_string(t
->key
, key_str
, sizeof key_str
);
322 log_struct(LOG_NOTICE
,
323 "MESSAGE_ID=" SD_MESSAGE_DNSSEC_FAILURE_STR
,
324 LOG_MESSAGE("DNSSEC validation failed for question %s: %s", key_str
, dnssec_result_to_string(t
->answer_dnssec_result
)),
325 "DNS_TRANSACTION=%" PRIu16
, t
->id
,
326 "DNS_QUESTION=%s", key_str
,
327 "DNSSEC_RESULT=%s", dnssec_result_to_string(t
->answer_dnssec_result
),
328 "DNS_SERVER=%s", dns_server_string(t
->server
),
329 "DNS_SERVER_FEATURE_LEVEL=%s", dns_server_feature_level_to_string(t
->server
->possible_feature_level
),
333 /* Note that this call might invalidate the query. Callers
334 * should hence not attempt to access the query or transaction
335 * after calling this function. */
337 if (state
== DNS_TRANSACTION_ERRNO
)
338 st
= errno_to_name(t
->answer_errno
);
340 st
= dns_transaction_state_to_string(state
);
342 log_debug("Transaction %" PRIu16
" for <%s> on scope %s on %s/%s now complete with <%s> from %s (%s).",
344 dns_resource_key_to_string(t
->key
, key_str
, sizeof key_str
),
345 dns_protocol_to_string(t
->scope
->protocol
),
346 t
->scope
->link
? t
->scope
->link
->name
: "*",
347 af_to_name_short(t
->scope
->family
),
349 t
->answer_source
< 0 ? "none" : dns_transaction_source_to_string(t
->answer_source
),
350 t
->answer_authenticated
? "authenticated" : "unsigned");
354 dns_transaction_close_connection(t
);
355 dns_transaction_stop_timeout(t
);
357 /* Notify all queries that are interested, but make sure the
358 * transaction isn't freed while we are still looking at it */
361 SET_FOREACH_MOVE(c
, t
->notify_query_candidates_done
, t
->notify_query_candidates
)
362 dns_query_candidate_notify(c
);
363 SWAP_TWO(t
->notify_query_candidates
, t
->notify_query_candidates_done
);
365 SET_FOREACH_MOVE(z
, t
->notify_zone_items_done
, t
->notify_zone_items
)
366 dns_zone_item_notify(z
);
367 SWAP_TWO(t
->notify_zone_items
, t
->notify_zone_items_done
);
368 if (t
->probing
&& t
->state
== DNS_TRANSACTION_ATTEMPTS_MAX_REACHED
)
369 (void) dns_scope_announce(t
->scope
, false);
371 SET_FOREACH_MOVE(d
, t
->notify_transactions_done
, t
->notify_transactions
)
372 dns_transaction_notify(d
, t
);
373 SWAP_TWO(t
->notify_transactions
, t
->notify_transactions_done
);
376 dns_transaction_gc(t
);
379 static int dns_transaction_pick_server(DnsTransaction
*t
) {
383 assert(t
->scope
->protocol
== DNS_PROTOCOL_DNS
);
385 /* Pick a DNS server and a feature level for it. */
387 server
= dns_scope_get_dns_server(t
->scope
);
391 /* If we changed the server invalidate the feature level clamping, as the new server might have completely
392 * different properties. */
393 if (server
!= t
->server
)
394 t
->clamp_feature_level
= _DNS_SERVER_FEATURE_LEVEL_INVALID
;
396 t
->current_feature_level
= dns_server_possible_feature_level(server
);
398 /* Clamp the feature level if that is requested. */
399 if (t
->clamp_feature_level
!= _DNS_SERVER_FEATURE_LEVEL_INVALID
&&
400 t
->current_feature_level
> t
->clamp_feature_level
)
401 t
->current_feature_level
= t
->clamp_feature_level
;
403 log_debug("Using feature level %s for transaction %u.", dns_server_feature_level_to_string(t
->current_feature_level
), t
->id
);
405 if (server
== t
->server
)
408 dns_server_unref(t
->server
);
409 t
->server
= dns_server_ref(server
);
411 t
->n_picked_servers
++;
413 log_debug("Using DNS server %s for transaction %u.", dns_server_string(t
->server
), t
->id
);
418 static void dns_transaction_retry(DnsTransaction
*t
, bool next_server
) {
423 log_debug("Retrying transaction %" PRIu16
".", t
->id
);
425 /* Before we try again, switch to a new server. */
427 dns_scope_next_dns_server(t
->scope
);
429 r
= dns_transaction_go(t
);
431 t
->answer_errno
= -r
;
432 dns_transaction_complete(t
, DNS_TRANSACTION_ERRNO
);
436 static int dns_transaction_maybe_restart(DnsTransaction
*t
) {
441 /* Returns > 0 if the transaction was restarted, 0 if not */
446 if (t
->current_feature_level
<= dns_server_possible_feature_level(t
->server
))
449 /* The server's current feature level is lower than when we sent the original query. We learnt something from
450 the response or possibly an auxiliary DNSSEC response that we didn't know before. We take that as reason to
451 restart the whole transaction. This is a good idea to deal with servers that respond rubbish if we include
452 OPT RR or DO bit. One of these cases is documented here, for example:
453 https://open.nlnetlabs.nl/pipermail/dnssec-trigger/2014-November/000376.html */
455 log_debug("Server feature level is now lower than when we began our transaction. Restarting with new ID.");
456 dns_transaction_shuffle_id(t
);
458 r
= dns_transaction_go(t
);
465 static int on_stream_complete(DnsStream
*s
, int error
) {
466 _cleanup_(dns_packet_unrefp
) DnsPacket
*p
= NULL
;
470 assert(s
->transaction
);
472 /* Copy the data we care about out of the stream before we
475 p
= dns_packet_ref(s
->read_packet
);
477 dns_transaction_close_connection(t
);
479 if (ERRNO_IS_DISCONNECT(error
)) {
482 if (t
->scope
->protocol
== DNS_PROTOCOL_LLMNR
) {
483 /* If the LLMNR/TCP connection failed, the host doesn't support LLMNR, and we cannot answer the
484 * question on this scope. */
485 dns_transaction_complete(t
, DNS_TRANSACTION_NOT_FOUND
);
489 log_debug_errno(error
, "Connection failure for DNS TCP stream: %m");
490 assert_se(sd_event_now(t
->scope
->manager
->event
, clock_boottime_or_monotonic(), &usec
) >= 0);
491 dns_server_packet_lost(t
->server
, IPPROTO_TCP
, t
->current_feature_level
, usec
- t
->start_usec
);
493 dns_transaction_retry(t
, true);
497 t
->answer_errno
= error
;
498 dns_transaction_complete(t
, DNS_TRANSACTION_ERRNO
);
502 if (dns_packet_validate_reply(p
) <= 0) {
503 log_debug("Invalid TCP reply packet.");
504 dns_transaction_complete(t
, DNS_TRANSACTION_INVALID_REPLY
);
508 dns_scope_check_conflicts(t
->scope
, p
);
511 dns_transaction_process_reply(t
, p
);
514 /* If the response wasn't useful, then complete the transition
515 * now. After all, we are the worst feature set now with TCP
516 * sockets, and there's really no point in retrying. */
517 if (t
->state
== DNS_TRANSACTION_PENDING
)
518 dns_transaction_complete(t
, DNS_TRANSACTION_INVALID_REPLY
);
520 dns_transaction_gc(t
);
525 static int dns_transaction_open_tcp(DnsTransaction
*t
) {
526 _cleanup_close_
int fd
= -1;
531 dns_transaction_close_connection(t
);
533 switch (t
->scope
->protocol
) {
535 case DNS_PROTOCOL_DNS
:
536 r
= dns_transaction_pick_server(t
);
540 if (!dns_server_dnssec_supported(t
->server
) && dns_type_is_dnssec(t
->key
->type
))
543 r
= dns_server_adjust_opt(t
->server
, t
->sent
, t
->current_feature_level
);
547 fd
= dns_scope_socket_tcp(t
->scope
, AF_UNSPEC
, NULL
, t
->server
, 53);
550 case DNS_PROTOCOL_LLMNR
:
551 /* When we already received a reply to this (but it was truncated), send to its sender address */
553 fd
= dns_scope_socket_tcp(t
->scope
, t
->received
->family
, &t
->received
->sender
, NULL
, t
->received
->sender_port
);
555 union in_addr_union address
;
556 int family
= AF_UNSPEC
;
558 /* Otherwise, try to talk to the owner of a
559 * the IP address, in case this is a reverse
562 r
= dns_name_address(dns_resource_key_name(t
->key
), &family
, &address
);
567 if (family
!= t
->scope
->family
)
570 fd
= dns_scope_socket_tcp(t
->scope
, family
, &address
, NULL
, LLMNR_PORT
);
576 return -EAFNOSUPPORT
;
582 r
= dns_stream_new(t
->scope
->manager
, &t
->stream
, t
->scope
->protocol
, fd
);
587 r
= dns_stream_write_packet(t
->stream
, t
->sent
);
589 t
->stream
= dns_stream_unref(t
->stream
);
593 t
->stream
->complete
= on_stream_complete
;
594 t
->stream
->transaction
= t
;
596 /* The interface index is difficult to determine if we are
597 * connecting to the local host, hence fill this in right away
598 * instead of determining it from the socket */
599 t
->stream
->ifindex
= dns_scope_ifindex(t
->scope
);
601 dns_transaction_reset_answer(t
);
603 t
->tried_stream
= true;
608 static void dns_transaction_cache_answer(DnsTransaction
*t
) {
611 /* For mDNS we cache whenever we get the packet, rather than
612 * in each transaction. */
613 if (!IN_SET(t
->scope
->protocol
, DNS_PROTOCOL_DNS
, DNS_PROTOCOL_LLMNR
))
616 /* Caching disabled? */
617 if (!t
->scope
->manager
->enable_cache
)
620 /* We never cache if this packet is from the local host, under
621 * the assumption that a locally running DNS server would
622 * cache this anyway, and probably knows better when to flush
623 * the cache then we could. */
624 if (!DNS_PACKET_SHALL_CACHE(t
->received
))
627 dns_cache_put(&t
->scope
->cache
,
631 t
->answer_authenticated
,
635 &t
->received
->sender
);
638 static bool dns_transaction_dnssec_is_live(DnsTransaction
*t
) {
644 SET_FOREACH(dt
, t
->dnssec_transactions
, i
)
645 if (DNS_TRANSACTION_IS_LIVE(dt
->state
))
651 static int dns_transaction_dnssec_ready(DnsTransaction
*t
) {
657 /* Checks whether the auxiliary DNSSEC transactions of our transaction have completed, or are still
658 * ongoing. Returns 0, if we aren't ready for the DNSSEC validation, positive if we are. */
660 SET_FOREACH(dt
, t
->dnssec_transactions
, i
) {
664 case DNS_TRANSACTION_NULL
:
665 case DNS_TRANSACTION_PENDING
:
666 case DNS_TRANSACTION_VALIDATING
:
670 case DNS_TRANSACTION_RCODE_FAILURE
:
671 if (!IN_SET(dt
->answer_rcode
, DNS_RCODE_NXDOMAIN
, DNS_RCODE_SERVFAIL
)) {
672 log_debug("Auxiliary DNSSEC RR query failed with rcode=%s.", dns_rcode_to_string(dt
->answer_rcode
));
676 /* Fall-through: NXDOMAIN/SERVFAIL is good enough for us. This is because some DNS servers
677 * erronously return NXDOMAIN/SERVFAIL for empty non-terminals (Akamai...) or missing DS
678 * records (Facebook), and we need to handle that nicely, when asking for parent SOA or similar
679 * RRs to make unsigned proofs. */
681 case DNS_TRANSACTION_SUCCESS
:
685 case DNS_TRANSACTION_DNSSEC_FAILED
:
686 /* We handle DNSSEC failures different from other errors, as we care about the DNSSEC
687 * validationr result */
689 log_debug("Auxiliary DNSSEC RR query failed validation: %s", dnssec_result_to_string(dt
->answer_dnssec_result
));
690 t
->answer_dnssec_result
= dt
->answer_dnssec_result
; /* Copy error code over */
691 dns_transaction_complete(t
, DNS_TRANSACTION_DNSSEC_FAILED
);
696 log_debug("Auxiliary DNSSEC RR query failed with %s", dns_transaction_state_to_string(dt
->state
));
701 /* All is ready, we can go and validate */
705 t
->answer_dnssec_result
= DNSSEC_FAILED_AUXILIARY
;
706 dns_transaction_complete(t
, DNS_TRANSACTION_DNSSEC_FAILED
);
710 static void dns_transaction_process_dnssec(DnsTransaction
*t
) {
715 /* Are there ongoing DNSSEC transactions? If so, let's wait for them. */
716 r
= dns_transaction_dnssec_ready(t
);
719 if (r
== 0) /* We aren't ready yet (or one of our auxiliary transactions failed, and we shouldn't validate now */
722 /* See if we learnt things from the additional DNSSEC transactions, that we didn't know before, and better
723 * restart the lookup immediately. */
724 r
= dns_transaction_maybe_restart(t
);
727 if (r
> 0) /* Transaction got restarted... */
730 /* All our auxiliary DNSSEC transactions are complete now. Try
731 * to validate our RRset now. */
732 r
= dns_transaction_validate_dnssec(t
);
734 dns_transaction_complete(t
, DNS_TRANSACTION_INVALID_REPLY
);
740 if (t
->answer_dnssec_result
== DNSSEC_INCOMPATIBLE_SERVER
&&
741 t
->scope
->dnssec_mode
== DNSSEC_YES
) {
743 /* We are not in automatic downgrade mode, and the server is bad. Let's try a different server, maybe
746 if (t
->n_picked_servers
< dns_scope_get_n_dns_servers(t
->scope
)) {
747 /* We tried fewer servers on this transaction than we know, let's try another one then */
748 dns_transaction_retry(t
, true);
752 /* OK, let's give up, apparently all servers we tried didn't work. */
753 dns_transaction_complete(t
, DNS_TRANSACTION_DNSSEC_FAILED
);
757 if (!IN_SET(t
->answer_dnssec_result
,
758 _DNSSEC_RESULT_INVALID
, /* No DNSSEC validation enabled */
759 DNSSEC_VALIDATED
, /* Answer is signed and validated successfully */
760 DNSSEC_UNSIGNED
, /* Answer is right-fully unsigned */
761 DNSSEC_INCOMPATIBLE_SERVER
)) { /* Server does not do DNSSEC (Yay, we are downgrade attack vulnerable!) */
762 dns_transaction_complete(t
, DNS_TRANSACTION_DNSSEC_FAILED
);
766 if (t
->answer_dnssec_result
== DNSSEC_INCOMPATIBLE_SERVER
)
767 dns_server_warn_downgrade(t
->server
);
769 dns_transaction_cache_answer(t
);
771 if (t
->answer_rcode
== DNS_RCODE_SUCCESS
)
772 dns_transaction_complete(t
, DNS_TRANSACTION_SUCCESS
);
774 dns_transaction_complete(t
, DNS_TRANSACTION_RCODE_FAILURE
);
779 t
->answer_errno
= -r
;
780 dns_transaction_complete(t
, DNS_TRANSACTION_ERRNO
);
783 static int dns_transaction_has_positive_answer(DnsTransaction
*t
, DnsAnswerFlags
*flags
) {
788 /* Checks whether the answer is positive, i.e. either a direct
789 * answer to the question, or a CNAME/DNAME for it */
791 r
= dns_answer_match_key(t
->answer
, t
->key
, flags
);
795 r
= dns_answer_find_cname_or_dname(t
->answer
, t
->key
, NULL
, flags
);
802 static int dns_transaction_fix_rcode(DnsTransaction
*t
) {
807 /* Fix up the RCODE to SUCCESS if we get at least one matching RR in a response. Note that this contradicts the
808 * DNS RFCs a bit. Specifically, RFC 6604 Section 3 clarifies that the RCODE shall say something about a
809 * CNAME/DNAME chain element coming after the last chain element contained in the message, and not the first
810 * one included. However, it also indicates that not all DNS servers implement this correctly. Moreover, when
811 * using DNSSEC we usually only can prove the first element of a CNAME/DNAME chain anyway, hence let's settle
812 * on always processing the RCODE as referring to the immediate look-up we do, i.e. the first element of a
813 * CNAME/DNAME chain. This way, we uniformly handle CNAME/DNAME chains, regardless if the DNS server
814 * incorrectly implements RCODE, whether DNSSEC is in use, or whether the DNS server only supplied us with an
815 * incomplete CNAME/DNAME chain.
817 * Or in other words: if we get at least one positive reply in a message we patch NXDOMAIN to become SUCCESS,
818 * and then rely on the CNAME chasing logic to figure out that there's actually a CNAME error with a new
821 if (t
->answer_rcode
!= DNS_RCODE_NXDOMAIN
)
824 r
= dns_transaction_has_positive_answer(t
, NULL
);
828 t
->answer_rcode
= DNS_RCODE_SUCCESS
;
832 void dns_transaction_process_reply(DnsTransaction
*t
, DnsPacket
*p
) {
839 assert(t
->scope
->manager
);
841 if (t
->state
!= DNS_TRANSACTION_PENDING
)
844 /* Note that this call might invalidate the query. Callers
845 * should hence not attempt to access the query or transaction
846 * after calling this function. */
848 log_debug("Processing incoming packet on transaction %" PRIu16
". (rcode=%s)", t
->id
, dns_rcode_to_string(DNS_PACKET_RCODE(p
)));
850 switch (t
->scope
->protocol
) {
852 case DNS_PROTOCOL_LLMNR
:
853 /* For LLMNR we will not accept any packets from other interfaces */
855 if (p
->ifindex
!= dns_scope_ifindex(t
->scope
))
858 if (p
->family
!= t
->scope
->family
)
861 /* Tentative packets are not full responses but still
862 * useful for identifying uniqueness conflicts during
864 if (DNS_PACKET_LLMNR_T(p
)) {
865 dns_transaction_tentative(t
, p
);
871 case DNS_PROTOCOL_MDNS
:
872 /* For mDNS we will not accept any packets from other interfaces */
874 if (p
->ifindex
!= dns_scope_ifindex(t
->scope
))
877 if (p
->family
!= t
->scope
->family
)
882 case DNS_PROTOCOL_DNS
:
883 /* Note that we do not need to verify the
884 * addresses/port numbers of incoming traffic, as we
885 * invoked connect() on our UDP socket in which case
886 * the kernel already does the needed verification for
891 assert_not_reached("Invalid DNS protocol.");
894 if (t
->received
!= p
) {
895 dns_packet_unref(t
->received
);
896 t
->received
= dns_packet_ref(p
);
899 t
->answer_source
= DNS_TRANSACTION_NETWORK
;
901 if (p
->ipproto
== IPPROTO_TCP
) {
902 if (DNS_PACKET_TC(p
)) {
903 /* Truncated via TCP? Somebody must be fucking with us */
904 dns_transaction_complete(t
, DNS_TRANSACTION_INVALID_REPLY
);
908 if (DNS_PACKET_ID(p
) != t
->id
) {
909 /* Not the reply to our query? Somebody must be fucking with us */
910 dns_transaction_complete(t
, DNS_TRANSACTION_INVALID_REPLY
);
915 assert_se(sd_event_now(t
->scope
->manager
->event
, clock_boottime_or_monotonic(), &ts
) >= 0);
917 switch (t
->scope
->protocol
) {
919 case DNS_PROTOCOL_DNS
:
922 if (IN_SET(DNS_PACKET_RCODE(p
), DNS_RCODE_FORMERR
, DNS_RCODE_SERVFAIL
, DNS_RCODE_NOTIMP
)) {
924 /* Request failed, immediately try again with reduced features */
926 if (t
->current_feature_level
<= DNS_SERVER_FEATURE_LEVEL_UDP
) {
928 /* This was already at UDP feature level? If so, it doesn't make sense to downgrade
929 * this transaction anymore, but let's see if it might make sense to send the request
930 * to a different DNS server instead. If not let's process the response, and accept the
931 * rcode. Note that we don't retry on TCP, since that's a suitable way to mitigate
932 * packet loss, but is not going to give us better rcodes should we actually have
933 * managed to get them already at UDP level. */
935 if (t
->n_picked_servers
< dns_scope_get_n_dns_servers(t
->scope
)) {
936 /* We tried fewer servers on this transaction than we know, let's try another one then */
937 dns_transaction_retry(t
, true);
941 /* Give up, accept the rcode */
942 log_debug("Server returned error: %s", dns_rcode_to_string(DNS_PACKET_RCODE(p
)));
946 /* Reduce this feature level by one and try again. */
947 t
->clamp_feature_level
= t
->current_feature_level
- 1;
949 log_debug("Server returned error %s, retrying transaction with reduced feature level %s.",
950 dns_rcode_to_string(DNS_PACKET_RCODE(p
)),
951 dns_server_feature_level_to_string(t
->clamp_feature_level
));
953 dns_transaction_retry(t
, false /* use the same server */);
957 if (DNS_PACKET_RCODE(p
) == DNS_RCODE_REFUSED
) {
958 /* This server refused our request? If so, try again, use a different server */
959 log_debug("Server returned REFUSED, switching servers, and retrying.");
960 dns_transaction_retry(t
, true /* pick a new server */);
964 if (DNS_PACKET_TC(p
))
965 dns_server_packet_truncated(t
->server
, t
->current_feature_level
);
969 case DNS_PROTOCOL_LLMNR
:
970 case DNS_PROTOCOL_MDNS
:
971 dns_scope_packet_received(t
->scope
, ts
- t
->start_usec
);
975 assert_not_reached("Invalid DNS protocol.");
978 if (DNS_PACKET_TC(p
)) {
980 /* Truncated packets for mDNS are not allowed. Give up immediately. */
981 if (t
->scope
->protocol
== DNS_PROTOCOL_MDNS
) {
982 dns_transaction_complete(t
, DNS_TRANSACTION_INVALID_REPLY
);
986 log_debug("Reply truncated, retrying via TCP.");
988 /* Response was truncated, let's try again with good old TCP */
989 r
= dns_transaction_open_tcp(t
);
991 /* No servers found? Damn! */
992 dns_transaction_complete(t
, DNS_TRANSACTION_NO_SERVERS
);
995 if (r
== -EOPNOTSUPP
) {
996 /* Tried to ask for DNSSEC RRs, on a server that doesn't do DNSSEC */
997 dns_transaction_complete(t
, DNS_TRANSACTION_RR_TYPE_UNSUPPORTED
);
1001 /* On LLMNR, if we cannot connect to the host,
1002 * we immediately give up */
1003 if (t
->scope
->protocol
!= DNS_PROTOCOL_DNS
)
1006 /* On DNS, couldn't send? Try immediately again, with a new server */
1007 dns_transaction_retry(t
, true);
1013 /* After the superficial checks, actually parse the message. */
1014 r
= dns_packet_extract(p
);
1016 dns_transaction_complete(t
, DNS_TRANSACTION_INVALID_REPLY
);
1021 /* Report that we successfully received a valid packet with a good rcode after we initially got a bad
1022 * rcode and subsequently downgraded the protocol */
1024 if (IN_SET(DNS_PACKET_RCODE(p
), DNS_RCODE_SUCCESS
, DNS_RCODE_NXDOMAIN
) &&
1025 t
->clamp_feature_level
!= _DNS_SERVER_FEATURE_LEVEL_INVALID
)
1026 dns_server_packet_rcode_downgrade(t
->server
, t
->clamp_feature_level
);
1028 /* Report that the OPT RR was missing */
1030 dns_server_packet_bad_opt(t
->server
, t
->current_feature_level
);
1032 /* Report that we successfully received a packet */
1033 dns_server_packet_received(t
->server
, p
->ipproto
, t
->current_feature_level
, ts
- t
->start_usec
, p
->size
);
1036 /* See if we know things we didn't know before that indicate we better restart the lookup immediately. */
1037 r
= dns_transaction_maybe_restart(t
);
1040 if (r
> 0) /* Transaction got restarted... */
1043 if (IN_SET(t
->scope
->protocol
, DNS_PROTOCOL_DNS
, DNS_PROTOCOL_LLMNR
, DNS_PROTOCOL_MDNS
)) {
1045 /* When dealing with protocols other than mDNS only consider responses with
1046 * equivalent query section to the request. For mDNS this check doesn't make
1047 * sense, because the section 6 of RFC6762 states that "Multicast DNS responses MUST NOT
1048 * contain any questions in the Question Section". */
1049 if (t
->scope
->protocol
!= DNS_PROTOCOL_MDNS
) {
1050 r
= dns_packet_is_reply_for(p
, t
->key
);
1054 dns_transaction_complete(t
, DNS_TRANSACTION_INVALID_REPLY
);
1059 /* Install the answer as answer to the transaction */
1060 dns_answer_unref(t
->answer
);
1061 t
->answer
= dns_answer_ref(p
->answer
);
1062 t
->answer_rcode
= DNS_PACKET_RCODE(p
);
1063 t
->answer_dnssec_result
= _DNSSEC_RESULT_INVALID
;
1064 t
->answer_authenticated
= false;
1066 r
= dns_transaction_fix_rcode(t
);
1070 /* Block GC while starting requests for additional DNSSEC RRs */
1072 r
= dns_transaction_request_dnssec_keys(t
);
1075 /* Maybe the transaction is ready for GC'ing now? If so, free it and return. */
1076 if (!dns_transaction_gc(t
))
1079 /* Requesting additional keys might have resulted in
1080 * this transaction to fail, since the auxiliary
1081 * request failed for some reason. If so, we are not
1082 * in pending state anymore, and we should exit
1084 if (t
->state
!= DNS_TRANSACTION_PENDING
)
1089 /* There are DNSSEC transactions pending now. Update the state accordingly. */
1090 t
->state
= DNS_TRANSACTION_VALIDATING
;
1091 dns_transaction_close_connection(t
);
1092 dns_transaction_stop_timeout(t
);
1097 dns_transaction_process_dnssec(t
);
1101 t
->answer_errno
= -r
;
1102 dns_transaction_complete(t
, DNS_TRANSACTION_ERRNO
);
1105 static int on_dns_packet(sd_event_source
*s
, int fd
, uint32_t revents
, void *userdata
) {
1106 _cleanup_(dns_packet_unrefp
) DnsPacket
*p
= NULL
;
1107 DnsTransaction
*t
= userdata
;
1113 r
= manager_recv(t
->scope
->manager
, fd
, DNS_PROTOCOL_DNS
, &p
);
1114 if (ERRNO_IS_DISCONNECT(-r
)) {
1117 /* UDP connection failure get reported via ICMP and then are possible delivered to us on the next
1118 * recvmsg(). Treat this like a lost packet. */
1120 log_debug_errno(r
, "Connection failure for DNS UDP packet: %m");
1121 assert_se(sd_event_now(t
->scope
->manager
->event
, clock_boottime_or_monotonic(), &usec
) >= 0);
1122 dns_server_packet_lost(t
->server
, IPPROTO_UDP
, t
->current_feature_level
, usec
- t
->start_usec
);
1124 dns_transaction_retry(t
, true);
1128 dns_transaction_complete(t
, DNS_TRANSACTION_ERRNO
);
1129 t
->answer_errno
= -r
;
1133 r
= dns_packet_validate_reply(p
);
1135 log_debug_errno(r
, "Received invalid DNS packet as response, ignoring: %m");
1139 log_debug("Received inappropriate DNS packet as response, ignoring.");
1143 if (DNS_PACKET_ID(p
) != t
->id
) {
1144 log_debug("Received packet with incorrect transaction ID, ignoring.");
1148 dns_transaction_process_reply(t
, p
);
1152 static int dns_transaction_emit_udp(DnsTransaction
*t
) {
1157 if (t
->scope
->protocol
== DNS_PROTOCOL_DNS
) {
1159 r
= dns_transaction_pick_server(t
);
1163 if (t
->current_feature_level
< DNS_SERVER_FEATURE_LEVEL_UDP
)
1164 return -EAGAIN
; /* Sorry, can't do UDP, try TCP! */
1166 if (!dns_server_dnssec_supported(t
->server
) && dns_type_is_dnssec(t
->key
->type
))
1169 if (r
> 0 || t
->dns_udp_fd
< 0) { /* Server changed, or no connection yet. */
1172 dns_transaction_close_connection(t
);
1174 fd
= dns_scope_socket_udp(t
->scope
, t
->server
, 53);
1178 r
= sd_event_add_io(t
->scope
->manager
->event
, &t
->dns_udp_event_source
, fd
, EPOLLIN
, on_dns_packet
, t
);
1184 (void) sd_event_source_set_description(t
->dns_udp_event_source
, "dns-transaction-udp");
1188 r
= dns_server_adjust_opt(t
->server
, t
->sent
, t
->current_feature_level
);
1192 dns_transaction_close_connection(t
);
1194 r
= dns_scope_emit_udp(t
->scope
, t
->dns_udp_fd
, t
->sent
);
1198 dns_transaction_reset_answer(t
);
1203 static int on_transaction_timeout(sd_event_source
*s
, usec_t usec
, void *userdata
) {
1204 DnsTransaction
*t
= userdata
;
1209 if (!t
->initial_jitter_scheduled
|| t
->initial_jitter_elapsed
) {
1210 /* Timeout reached? Increase the timeout for the server used */
1211 switch (t
->scope
->protocol
) {
1213 case DNS_PROTOCOL_DNS
:
1215 dns_server_packet_lost(t
->server
, t
->stream
? IPPROTO_TCP
: IPPROTO_UDP
, t
->current_feature_level
, usec
- t
->start_usec
);
1218 case DNS_PROTOCOL_LLMNR
:
1219 case DNS_PROTOCOL_MDNS
:
1220 dns_scope_packet_lost(t
->scope
, usec
- t
->start_usec
);
1224 assert_not_reached("Invalid DNS protocol.");
1227 if (t
->initial_jitter_scheduled
)
1228 t
->initial_jitter_elapsed
= true;
1231 log_debug("Timeout reached on transaction %" PRIu16
".", t
->id
);
1233 dns_transaction_retry(t
, true);
1237 static usec_t
transaction_get_resend_timeout(DnsTransaction
*t
) {
1242 switch (t
->scope
->protocol
) {
1244 case DNS_PROTOCOL_DNS
:
1246 /* When we do TCP, grant a much longer timeout, as in this case there's no need for us to quickly
1247 * resend, as the kernel does that anyway for us, and we really don't want to interrupt it in that
1250 return TRANSACTION_TCP_TIMEOUT_USEC
;
1253 return t
->server
->resend_timeout
;
1255 case DNS_PROTOCOL_MDNS
:
1256 assert(t
->n_attempts
> 0);
1258 return MDNS_PROBING_INTERVAL_USEC
;
1260 return (1 << (t
->n_attempts
- 1)) * USEC_PER_SEC
;
1262 case DNS_PROTOCOL_LLMNR
:
1263 return t
->scope
->resend_timeout
;
1266 assert_not_reached("Invalid DNS protocol.");
1270 static int dns_transaction_prepare(DnsTransaction
*t
, usec_t ts
) {
1275 dns_transaction_stop_timeout(t
);
1277 r
= dns_scope_network_good(t
->scope
);
1281 dns_transaction_complete(t
, DNS_TRANSACTION_NETWORK_DOWN
);
1285 if (t
->n_attempts
>= TRANSACTION_ATTEMPTS_MAX(t
->scope
->protocol
)) {
1286 dns_transaction_complete(t
, DNS_TRANSACTION_ATTEMPTS_MAX_REACHED
);
1290 if (t
->scope
->protocol
== DNS_PROTOCOL_LLMNR
&& t
->tried_stream
) {
1291 /* If we already tried via a stream, then we don't
1292 * retry on LLMNR. See RFC 4795, Section 2.7. */
1293 dns_transaction_complete(t
, DNS_TRANSACTION_ATTEMPTS_MAX_REACHED
);
1300 dns_transaction_reset_answer(t
);
1301 dns_transaction_flush_dnssec_transactions(t
);
1303 /* Check the trust anchor. Do so only on classic DNS, since DNSSEC does not apply otherwise. */
1304 if (t
->scope
->protocol
== DNS_PROTOCOL_DNS
) {
1305 r
= dns_trust_anchor_lookup_positive(&t
->scope
->manager
->trust_anchor
, t
->key
, &t
->answer
);
1309 t
->answer_rcode
= DNS_RCODE_SUCCESS
;
1310 t
->answer_source
= DNS_TRANSACTION_TRUST_ANCHOR
;
1311 t
->answer_authenticated
= true;
1312 dns_transaction_complete(t
, DNS_TRANSACTION_SUCCESS
);
1316 if (dns_name_is_root(dns_resource_key_name(t
->key
)) &&
1317 t
->key
->type
== DNS_TYPE_DS
) {
1319 /* Hmm, this is a request for the root DS? A
1320 * DS RR doesn't exist in the root zone, and
1321 * if our trust anchor didn't know it either,
1322 * this means we cannot do any DNSSEC logic
1325 if (t
->scope
->dnssec_mode
== DNSSEC_ALLOW_DOWNGRADE
) {
1326 /* We are in downgrade mode. In this
1327 * case, synthesize an unsigned empty
1328 * response, so that the any lookup
1329 * depending on this one can continue
1330 * assuming there was no DS, and hence
1331 * the root zone was unsigned. */
1333 t
->answer_rcode
= DNS_RCODE_SUCCESS
;
1334 t
->answer_source
= DNS_TRANSACTION_TRUST_ANCHOR
;
1335 t
->answer_authenticated
= false;
1336 dns_transaction_complete(t
, DNS_TRANSACTION_SUCCESS
);
1338 /* If we are not in downgrade mode,
1339 * then fail the lookup, because we
1340 * cannot reasonably answer it. There
1341 * might be DS RRs, but we don't know
1342 * them, and the DNS server won't tell
1343 * them to us (and even if it would,
1344 * we couldn't validate and trust them. */
1345 dns_transaction_complete(t
, DNS_TRANSACTION_NO_TRUST_ANCHOR
);
1351 /* Check the zone, but only if this transaction is not used
1352 * for probing or verifying a zone item. */
1353 if (set_isempty(t
->notify_zone_items
)) {
1355 r
= dns_zone_lookup(&t
->scope
->zone
, t
->key
, dns_scope_ifindex(t
->scope
), &t
->answer
, NULL
, NULL
);
1359 t
->answer_rcode
= DNS_RCODE_SUCCESS
;
1360 t
->answer_source
= DNS_TRANSACTION_ZONE
;
1361 t
->answer_authenticated
= true;
1362 dns_transaction_complete(t
, DNS_TRANSACTION_SUCCESS
);
1367 /* Check the cache, but only if this transaction is not used
1368 * for probing or verifying a zone item. */
1369 if (set_isempty(t
->notify_zone_items
)) {
1371 /* Before trying the cache, let's make sure we figured out a
1372 * server to use. Should this cause a change of server this
1373 * might flush the cache. */
1374 (void) dns_scope_get_dns_server(t
->scope
);
1376 /* Let's then prune all outdated entries */
1377 dns_cache_prune(&t
->scope
->cache
);
1379 r
= dns_cache_lookup(&t
->scope
->cache
, t
->key
, t
->clamp_ttl
, &t
->answer_rcode
, &t
->answer
, &t
->answer_authenticated
);
1383 t
->answer_source
= DNS_TRANSACTION_CACHE
;
1384 if (t
->answer_rcode
== DNS_RCODE_SUCCESS
)
1385 dns_transaction_complete(t
, DNS_TRANSACTION_SUCCESS
);
1387 dns_transaction_complete(t
, DNS_TRANSACTION_RCODE_FAILURE
);
1395 static int dns_transaction_make_packet_mdns(DnsTransaction
*t
) {
1397 _cleanup_(dns_packet_unrefp
) DnsPacket
*p
= NULL
;
1398 bool add_known_answers
= false;
1399 DnsTransaction
*other
;
1401 DnsResourceKey
*tkey
;
1402 _cleanup_set_free_ Set
*keys
= NULL
;
1404 unsigned nscount
= 0;
1409 assert(t
->scope
->protocol
== DNS_PROTOCOL_MDNS
);
1411 /* Discard any previously prepared packet, so we can start over and coalesce again */
1412 t
->sent
= dns_packet_unref(t
->sent
);
1414 r
= dns_packet_new_query(&p
, t
->scope
->protocol
, 0, false);
1418 r
= dns_packet_append_key(p
, t
->key
, 0, NULL
);
1424 if (dns_key_is_shared(t
->key
))
1425 add_known_answers
= true;
1427 if (t
->key
->type
== DNS_TYPE_ANY
) {
1428 r
= set_ensure_allocated(&keys
, &dns_resource_key_hash_ops
);
1432 r
= set_put(keys
, t
->key
);
1438 * For mDNS, we want to coalesce as many open queries in pending transactions into one single
1439 * query packet on the wire as possible. To achieve that, we iterate through all pending transactions
1440 * in our current scope, and see whether their timing contraints allow them to be sent.
1443 assert_se(sd_event_now(t
->scope
->manager
->event
, clock_boottime_or_monotonic(), &ts
) >= 0);
1445 LIST_FOREACH(transactions_by_scope
, other
, t
->scope
->transactions
) {
1447 /* Skip ourselves */
1451 if (other
->state
!= DNS_TRANSACTION_PENDING
)
1454 if (other
->next_attempt_after
> ts
)
1457 if (qdcount
>= UINT16_MAX
)
1460 r
= dns_packet_append_key(p
, other
->key
, 0, NULL
);
1463 * If we can't stuff more questions into the packet, just give up.
1464 * One of the 'other' transactions will fire later and take care of the rest.
1472 r
= dns_transaction_prepare(other
, ts
);
1476 ts
+= transaction_get_resend_timeout(other
);
1478 r
= sd_event_add_time(
1479 other
->scope
->manager
->event
,
1480 &other
->timeout_event_source
,
1481 clock_boottime_or_monotonic(),
1483 on_transaction_timeout
, other
);
1487 (void) sd_event_source_set_description(other
->timeout_event_source
, "dns-transaction-timeout");
1489 other
->state
= DNS_TRANSACTION_PENDING
;
1490 other
->next_attempt_after
= ts
;
1494 if (dns_key_is_shared(other
->key
))
1495 add_known_answers
= true;
1497 if (other
->key
->type
== DNS_TYPE_ANY
) {
1498 r
= set_ensure_allocated(&keys
, &dns_resource_key_hash_ops
);
1502 r
= set_put(keys
, other
->key
);
1508 DNS_PACKET_HEADER(p
)->qdcount
= htobe16(qdcount
);
1510 /* Append known answer section if we're asking for any shared record */
1511 if (add_known_answers
) {
1512 r
= dns_cache_export_shared_to_packet(&t
->scope
->cache
, p
);
1517 SET_FOREACH(tkey
, keys
, i
) {
1518 _cleanup_(dns_answer_unrefp
) DnsAnswer
*answer
= NULL
;
1521 r
= dns_zone_lookup(&t
->scope
->zone
, tkey
, t
->scope
->link
->ifindex
, &answer
, NULL
, &tentative
);
1525 r
= dns_packet_append_answer(p
, answer
);
1529 nscount
+= dns_answer_size(answer
);
1531 DNS_PACKET_HEADER(p
)->nscount
= htobe16(nscount
);
1539 static int dns_transaction_make_packet(DnsTransaction
*t
) {
1540 _cleanup_(dns_packet_unrefp
) DnsPacket
*p
= NULL
;
1545 if (t
->scope
->protocol
== DNS_PROTOCOL_MDNS
)
1546 return dns_transaction_make_packet_mdns(t
);
1551 r
= dns_packet_new_query(&p
, t
->scope
->protocol
, 0, t
->scope
->dnssec_mode
!= DNSSEC_NO
);
1555 r
= dns_packet_append_key(p
, t
->key
, 0, NULL
);
1559 DNS_PACKET_HEADER(p
)->qdcount
= htobe16(1);
1560 DNS_PACKET_HEADER(p
)->id
= t
->id
;
1568 int dns_transaction_go(DnsTransaction
*t
) {
1571 char key_str
[DNS_RESOURCE_KEY_STRING_MAX
];
1575 /* Returns > 0 if the transaction is now pending, returns 0 if could be processed immediately and has finished
1578 assert_se(sd_event_now(t
->scope
->manager
->event
, clock_boottime_or_monotonic(), &ts
) >= 0);
1580 r
= dns_transaction_prepare(t
, ts
);
1584 log_debug("Transaction %" PRIu16
" for <%s> scope %s on %s/%s.",
1586 dns_resource_key_to_string(t
->key
, key_str
, sizeof key_str
),
1587 dns_protocol_to_string(t
->scope
->protocol
),
1588 t
->scope
->link
? t
->scope
->link
->name
: "*",
1589 af_to_name_short(t
->scope
->family
));
1591 if (!t
->initial_jitter_scheduled
&&
1592 IN_SET(t
->scope
->protocol
, DNS_PROTOCOL_LLMNR
, DNS_PROTOCOL_MDNS
)) {
1593 usec_t jitter
, accuracy
;
1595 /* RFC 4795 Section 2.7 suggests all queries should be
1596 * delayed by a random time from 0 to JITTER_INTERVAL. */
1598 t
->initial_jitter_scheduled
= true;
1600 random_bytes(&jitter
, sizeof(jitter
));
1602 switch (t
->scope
->protocol
) {
1604 case DNS_PROTOCOL_LLMNR
:
1605 jitter
%= LLMNR_JITTER_INTERVAL_USEC
;
1606 accuracy
= LLMNR_JITTER_INTERVAL_USEC
;
1609 case DNS_PROTOCOL_MDNS
:
1610 jitter
%= MDNS_JITTER_RANGE_USEC
;
1611 jitter
+= MDNS_JITTER_MIN_USEC
;
1612 accuracy
= MDNS_JITTER_RANGE_USEC
;
1615 assert_not_reached("bad protocol");
1618 r
= sd_event_add_time(
1619 t
->scope
->manager
->event
,
1620 &t
->timeout_event_source
,
1621 clock_boottime_or_monotonic(),
1622 ts
+ jitter
, accuracy
,
1623 on_transaction_timeout
, t
);
1627 (void) sd_event_source_set_description(t
->timeout_event_source
, "dns-transaction-timeout");
1630 t
->next_attempt_after
= ts
;
1631 t
->state
= DNS_TRANSACTION_PENDING
;
1633 log_debug("Delaying %s transaction for " USEC_FMT
"us.", dns_protocol_to_string(t
->scope
->protocol
), jitter
);
1637 /* Otherwise, we need to ask the network */
1638 r
= dns_transaction_make_packet(t
);
1642 if (t
->scope
->protocol
== DNS_PROTOCOL_LLMNR
&&
1643 (dns_name_endswith(dns_resource_key_name(t
->key
), "in-addr.arpa") > 0 ||
1644 dns_name_endswith(dns_resource_key_name(t
->key
), "ip6.arpa") > 0)) {
1646 /* RFC 4795, Section 2.4. says reverse lookups shall
1647 * always be made via TCP on LLMNR */
1648 r
= dns_transaction_open_tcp(t
);
1650 /* Try via UDP, and if that fails due to large size or lack of
1651 * support try via TCP */
1652 r
= dns_transaction_emit_udp(t
);
1654 log_debug("Sending query via TCP since it is too large.");
1655 else if (r
== -EAGAIN
)
1656 log_debug("Sending query via TCP since server doesn't support UDP.");
1657 if (IN_SET(r
, -EMSGSIZE
, -EAGAIN
))
1658 r
= dns_transaction_open_tcp(t
);
1662 /* No servers to send this to? */
1663 dns_transaction_complete(t
, DNS_TRANSACTION_NO_SERVERS
);
1666 if (r
== -EOPNOTSUPP
) {
1667 /* Tried to ask for DNSSEC RRs, on a server that doesn't do DNSSEC */
1668 dns_transaction_complete(t
, DNS_TRANSACTION_RR_TYPE_UNSUPPORTED
);
1671 if (t
->scope
->protocol
== DNS_PROTOCOL_LLMNR
&& ERRNO_IS_DISCONNECT(-r
)) {
1672 /* On LLMNR, if we cannot connect to a host via TCP when doing reverse lookups. This means we cannot
1673 * answer this request with this protocol. */
1674 dns_transaction_complete(t
, DNS_TRANSACTION_NOT_FOUND
);
1678 if (t
->scope
->protocol
!= DNS_PROTOCOL_DNS
)
1681 /* Couldn't send? Try immediately again, with a new server */
1682 dns_scope_next_dns_server(t
->scope
);
1684 return dns_transaction_go(t
);
1687 ts
+= transaction_get_resend_timeout(t
);
1689 r
= sd_event_add_time(
1690 t
->scope
->manager
->event
,
1691 &t
->timeout_event_source
,
1692 clock_boottime_or_monotonic(),
1694 on_transaction_timeout
, t
);
1698 (void) sd_event_source_set_description(t
->timeout_event_source
, "dns-transaction-timeout");
1700 t
->state
= DNS_TRANSACTION_PENDING
;
1701 t
->next_attempt_after
= ts
;
1706 static int dns_transaction_find_cyclic(DnsTransaction
*t
, DnsTransaction
*aux
) {
1714 /* Try to find cyclic dependencies between transaction objects */
1719 SET_FOREACH(n
, aux
->dnssec_transactions
, i
) {
1720 r
= dns_transaction_find_cyclic(t
, n
);
1728 static int dns_transaction_add_dnssec_transaction(DnsTransaction
*t
, DnsResourceKey
*key
, DnsTransaction
**ret
) {
1729 DnsTransaction
*aux
;
1736 aux
= dns_scope_find_transaction(t
->scope
, key
, true);
1738 r
= dns_transaction_new(&aux
, t
->scope
, key
);
1742 if (set_contains(t
->dnssec_transactions
, aux
)) {
1747 r
= dns_transaction_find_cyclic(t
, aux
);
1751 char s
[DNS_RESOURCE_KEY_STRING_MAX
], saux
[DNS_RESOURCE_KEY_STRING_MAX
];
1753 log_debug("Potential cyclic dependency, refusing to add transaction %" PRIu16
" (%s) as dependency for %" PRIu16
" (%s).",
1755 dns_resource_key_to_string(t
->key
, s
, sizeof s
),
1757 dns_resource_key_to_string(aux
->key
, saux
, sizeof saux
));
1763 r
= set_ensure_allocated(&t
->dnssec_transactions
, NULL
);
1767 r
= set_ensure_allocated(&aux
->notify_transactions
, NULL
);
1771 r
= set_ensure_allocated(&aux
->notify_transactions_done
, NULL
);
1775 r
= set_put(t
->dnssec_transactions
, aux
);
1779 r
= set_put(aux
->notify_transactions
, t
);
1781 (void) set_remove(t
->dnssec_transactions
, aux
);
1789 dns_transaction_gc(aux
);
1793 static int dns_transaction_request_dnssec_rr(DnsTransaction
*t
, DnsResourceKey
*key
) {
1794 _cleanup_(dns_answer_unrefp
) DnsAnswer
*a
= NULL
;
1795 DnsTransaction
*aux
;
1801 /* Try to get the data from the trust anchor */
1802 r
= dns_trust_anchor_lookup_positive(&t
->scope
->manager
->trust_anchor
, key
, &a
);
1806 r
= dns_answer_extend(&t
->validated_keys
, a
);
1813 /* This didn't work, ask for it via the network/cache then. */
1814 r
= dns_transaction_add_dnssec_transaction(t
, key
, &aux
);
1815 if (r
== -ELOOP
) /* This would result in a cyclic dependency */
1820 if (aux
->state
== DNS_TRANSACTION_NULL
) {
1821 r
= dns_transaction_go(aux
);
1829 static int dns_transaction_negative_trust_anchor_lookup(DnsTransaction
*t
, const char *name
) {
1834 /* Check whether the specified name is in the NTA
1835 * database, either in the global one, or the link-local
1838 r
= dns_trust_anchor_lookup_negative(&t
->scope
->manager
->trust_anchor
, name
);
1842 if (!t
->scope
->link
)
1845 return set_contains(t
->scope
->link
->dnssec_negative_trust_anchors
, name
);
1848 static int dns_transaction_has_unsigned_negative_answer(DnsTransaction
*t
) {
1853 /* Checks whether the answer is negative, and lacks NSEC/NSEC3
1854 * RRs to prove it */
1856 r
= dns_transaction_has_positive_answer(t
, NULL
);
1862 /* Is this key explicitly listed as a negative trust anchor?
1863 * If so, it's nothing we need to care about */
1864 r
= dns_transaction_negative_trust_anchor_lookup(t
, dns_resource_key_name(t
->key
));
1870 /* The answer does not contain any RRs that match to the
1871 * question. If so, let's see if there are any NSEC/NSEC3 RRs
1872 * included. If not, the answer is unsigned. */
1874 r
= dns_answer_contains_nsec_or_nsec3(t
->answer
);
1883 static int dns_transaction_is_primary_response(DnsTransaction
*t
, DnsResourceRecord
*rr
) {
1889 /* Check if the specified RR is the "primary" response,
1890 * i.e. either matches the question precisely or is a
1891 * CNAME/DNAME for it. */
1893 r
= dns_resource_key_match_rr(t
->key
, rr
, NULL
);
1897 return dns_resource_key_match_cname_or_dname(t
->key
, rr
->key
, NULL
);
1900 static bool dns_transaction_dnssec_supported(DnsTransaction
*t
) {
1903 /* Checks whether our transaction's DNS server is assumed to be compatible with DNSSEC. Returns false as soon
1904 * as we changed our mind about a server, and now believe it is incompatible with DNSSEC. */
1906 if (t
->scope
->protocol
!= DNS_PROTOCOL_DNS
)
1909 /* If we have picked no server, then we are working from the cache or some other source, and DNSSEC might well
1910 * be supported, hence return true. */
1914 /* Note that we do not check the feature level actually used for the transaction but instead the feature level
1915 * the server is known to support currently, as the transaction feature level might be lower than what the
1916 * server actually supports, since we might have downgraded this transaction's feature level because we got a
1917 * SERVFAIL earlier and wanted to check whether downgrading fixes it. */
1919 return dns_server_dnssec_supported(t
->server
);
1922 static bool dns_transaction_dnssec_supported_full(DnsTransaction
*t
) {
1928 /* Checks whether our transaction our any of the auxiliary transactions couldn't do DNSSEC. */
1930 if (!dns_transaction_dnssec_supported(t
))
1933 SET_FOREACH(dt
, t
->dnssec_transactions
, i
)
1934 if (!dns_transaction_dnssec_supported(dt
))
1940 int dns_transaction_request_dnssec_keys(DnsTransaction
*t
) {
1941 DnsResourceRecord
*rr
;
1948 * Retrieve all auxiliary RRs for the answer we got, so that
1949 * we can verify signatures or prove that RRs are rightfully
1950 * unsigned. Specifically:
1952 * - For RRSIG we get the matching DNSKEY
1953 * - For DNSKEY we get the matching DS
1954 * - For unsigned SOA/NS we get the matching DS
1955 * - For unsigned CNAME/DNAME/DS we get the parent SOA RR
1956 * - For other unsigned RRs we get the matching SOA RR
1957 * - For SOA/NS queries with no matching response RR, and no NSEC/NSEC3, the DS RR
1958 * - For DS queries with no matching response RRs, and no NSEC/NSEC3, the parent's SOA RR
1959 * - For other queries with no matching response RRs, and no NSEC/NSEC3, the SOA RR
1962 if (t
->scope
->dnssec_mode
== DNSSEC_NO
)
1964 if (t
->answer_source
!= DNS_TRANSACTION_NETWORK
)
1965 return 0; /* We only need to validate stuff from the network */
1966 if (!dns_transaction_dnssec_supported(t
))
1967 return 0; /* If we can't do DNSSEC anyway there's no point in geting the auxiliary RRs */
1969 DNS_ANSWER_FOREACH(rr
, t
->answer
) {
1971 if (dns_type_is_pseudo(rr
->key
->type
))
1974 /* If this RR is in the negative trust anchor, we don't need to validate it. */
1975 r
= dns_transaction_negative_trust_anchor_lookup(t
, dns_resource_key_name(rr
->key
));
1981 switch (rr
->key
->type
) {
1983 case DNS_TYPE_RRSIG
: {
1984 /* For each RRSIG we request the matching DNSKEY */
1985 _cleanup_(dns_resource_key_unrefp
) DnsResourceKey
*dnskey
= NULL
;
1987 /* If this RRSIG is about a DNSKEY RR and the
1988 * signer is the same as the owner, then we
1989 * already have the DNSKEY, and we don't have
1990 * to look for more. */
1991 if (rr
->rrsig
.type_covered
== DNS_TYPE_DNSKEY
) {
1992 r
= dns_name_equal(rr
->rrsig
.signer
, dns_resource_key_name(rr
->key
));
1999 /* If the signer is not a parent of our
2000 * original query, then this is about an
2001 * auxiliary RRset, but not anything we asked
2002 * for. In this case we aren't interested,
2003 * because we don't want to request additional
2004 * RRs for stuff we didn't really ask for, and
2005 * also to avoid request loops, where
2006 * additional RRs from one transaction result
2007 * in another transaction whose additonal RRs
2008 * point back to the original transaction, and
2010 r
= dns_name_endswith(dns_resource_key_name(t
->key
), rr
->rrsig
.signer
);
2016 dnskey
= dns_resource_key_new(rr
->key
->class, DNS_TYPE_DNSKEY
, rr
->rrsig
.signer
);
2020 log_debug("Requesting DNSKEY to validate transaction %" PRIu16
" (%s, RRSIG with key tag: %" PRIu16
").",
2021 t
->id
, dns_resource_key_name(rr
->key
), rr
->rrsig
.key_tag
);
2022 r
= dns_transaction_request_dnssec_rr(t
, dnskey
);
2028 case DNS_TYPE_DNSKEY
: {
2029 /* For each DNSKEY we request the matching DS */
2030 _cleanup_(dns_resource_key_unrefp
) DnsResourceKey
*ds
= NULL
;
2032 /* If the DNSKEY we are looking at is not for
2033 * zone we are interested in, nor any of its
2034 * parents, we aren't interested, and don't
2035 * request it. After all, we don't want to end
2036 * up in request loops, and want to keep
2037 * additional traffic down. */
2039 r
= dns_name_endswith(dns_resource_key_name(t
->key
), dns_resource_key_name(rr
->key
));
2045 ds
= dns_resource_key_new(rr
->key
->class, DNS_TYPE_DS
, dns_resource_key_name(rr
->key
));
2049 log_debug("Requesting DS to validate transaction %" PRIu16
" (%s, DNSKEY with key tag: %" PRIu16
").",
2050 t
->id
, dns_resource_key_name(rr
->key
), dnssec_keytag(rr
, false));
2051 r
= dns_transaction_request_dnssec_rr(t
, ds
);
2060 _cleanup_(dns_resource_key_unrefp
) DnsResourceKey
*ds
= NULL
;
2062 /* For an unsigned SOA or NS, try to acquire
2063 * the matching DS RR, as we are at a zone cut
2064 * then, and whether a DS exists tells us
2065 * whether the zone is signed. Do so only if
2066 * this RR matches our original question,
2069 r
= dns_resource_key_match_rr(t
->key
, rr
, NULL
);
2073 /* Hmm, so this SOA RR doesn't match our original question. In this case, maybe this is
2074 * a negative reply, and we need the a SOA RR's TTL in order to cache a negative entry?
2075 * If so, we need to validate it, too. */
2077 r
= dns_answer_match_key(t
->answer
, t
->key
, NULL
);
2080 if (r
> 0) /* positive reply, we won't need the SOA and hence don't need to validate
2085 r
= dnssec_has_rrsig(t
->answer
, rr
->key
);
2091 ds
= dns_resource_key_new(rr
->key
->class, DNS_TYPE_DS
, dns_resource_key_name(rr
->key
));
2095 log_debug("Requesting DS to validate transaction %" PRIu16
" (%s, unsigned SOA/NS RRset).",
2096 t
->id
, dns_resource_key_name(rr
->key
));
2097 r
= dns_transaction_request_dnssec_rr(t
, ds
);
2105 case DNS_TYPE_CNAME
:
2106 case DNS_TYPE_DNAME
: {
2107 _cleanup_(dns_resource_key_unrefp
) DnsResourceKey
*soa
= NULL
;
2110 /* CNAMEs and DNAMEs cannot be located at a
2111 * zone apex, hence ask for the parent SOA for
2112 * unsigned CNAME/DNAME RRs, maybe that's the
2113 * apex. But do all that only if this is
2114 * actually a response to our original
2117 * Similar for DS RRs, which are signed when
2118 * the parent SOA is signed. */
2120 r
= dns_transaction_is_primary_response(t
, rr
);
2126 r
= dnssec_has_rrsig(t
->answer
, rr
->key
);
2132 r
= dns_answer_has_dname_for_cname(t
->answer
, rr
);
2138 name
= dns_resource_key_name(rr
->key
);
2139 r
= dns_name_parent(&name
);
2145 soa
= dns_resource_key_new(rr
->key
->class, DNS_TYPE_SOA
, name
);
2149 log_debug("Requesting parent SOA to validate transaction %" PRIu16
" (%s, unsigned CNAME/DNAME/DS RRset).",
2150 t
->id
, dns_resource_key_name(rr
->key
));
2151 r
= dns_transaction_request_dnssec_rr(t
, soa
);
2159 _cleanup_(dns_resource_key_unrefp
) DnsResourceKey
*soa
= NULL
;
2161 /* For other unsigned RRsets (including
2162 * NSEC/NSEC3!), look for proof the zone is
2163 * unsigned, by requesting the SOA RR of the
2164 * zone. However, do so only if they are
2165 * directly relevant to our original
2168 r
= dns_transaction_is_primary_response(t
, rr
);
2174 r
= dnssec_has_rrsig(t
->answer
, rr
->key
);
2180 soa
= dns_resource_key_new(rr
->key
->class, DNS_TYPE_SOA
, dns_resource_key_name(rr
->key
));
2184 log_debug("Requesting SOA to validate transaction %" PRIu16
" (%s, unsigned non-SOA/NS RRset <%s>).",
2185 t
->id
, dns_resource_key_name(rr
->key
), dns_resource_record_to_string(rr
));
2186 r
= dns_transaction_request_dnssec_rr(t
, soa
);
2193 /* Above, we requested everything necessary to validate what
2194 * we got. Now, let's request what we need to validate what we
2197 r
= dns_transaction_has_unsigned_negative_answer(t
);
2204 name
= dns_resource_key_name(t
->key
);
2206 /* If this was a SOA or NS request, then check if there's a DS RR for the same domain. Note that this
2207 * could also be used as indication that we are not at a zone apex, but in real world setups there are
2208 * too many broken DNS servers (Hello, incapdns.net!) where non-terminal zones return NXDOMAIN even
2209 * though they have further children. If this was a DS request, then it's signed when the parent zone
2210 * is signed, hence ask the parent SOA in that case. If this was any other RR then ask for the SOA RR,
2211 * to see if that is signed. */
2213 if (t
->key
->type
== DNS_TYPE_DS
) {
2214 r
= dns_name_parent(&name
);
2216 type
= DNS_TYPE_SOA
;
2217 log_debug("Requesting parent SOA to validate transaction %" PRIu16
" (%s, unsigned empty DS response).",
2218 t
->id
, dns_resource_key_name(t
->key
));
2222 } else if (IN_SET(t
->key
->type
, DNS_TYPE_SOA
, DNS_TYPE_NS
)) {
2225 log_debug("Requesting DS to validate transaction %" PRIu16
" (%s, unsigned empty SOA/NS response).",
2226 t
->id
, dns_resource_key_name(t
->key
));
2229 type
= DNS_TYPE_SOA
;
2230 log_debug("Requesting SOA to validate transaction %" PRIu16
" (%s, unsigned empty non-SOA/NS/DS response).",
2231 t
->id
, dns_resource_key_name(t
->key
));
2235 _cleanup_(dns_resource_key_unrefp
) DnsResourceKey
*soa
= NULL
;
2237 soa
= dns_resource_key_new(t
->key
->class, type
, name
);
2241 r
= dns_transaction_request_dnssec_rr(t
, soa
);
2247 return dns_transaction_dnssec_is_live(t
);
2250 void dns_transaction_notify(DnsTransaction
*t
, DnsTransaction
*source
) {
2254 /* Invoked whenever any of our auxiliary DNSSEC transactions completed its work. If the state is still PENDING,
2255 we are still in the loop that adds further DNSSEC transactions, hence don't check if we are ready yet. If
2256 the state is VALIDATING however, we should check if we are complete now. */
2258 if (t
->state
== DNS_TRANSACTION_VALIDATING
)
2259 dns_transaction_process_dnssec(t
);
2262 static int dns_transaction_validate_dnskey_by_ds(DnsTransaction
*t
) {
2263 DnsResourceRecord
*rr
;
2268 /* Add all DNSKEY RRs from the answer that are validated by DS
2269 * RRs from the list of validated keys to the list of
2270 * validated keys. */
2272 DNS_ANSWER_FOREACH_IFINDEX(rr
, ifindex
, t
->answer
) {
2274 r
= dnssec_verify_dnskey_by_ds_search(rr
, t
->validated_keys
);
2280 /* If so, the DNSKEY is validated too. */
2281 r
= dns_answer_add_extend(&t
->validated_keys
, rr
, ifindex
, DNS_ANSWER_AUTHENTICATED
);
2289 static int dns_transaction_requires_rrsig(DnsTransaction
*t
, DnsResourceRecord
*rr
) {
2295 /* Checks if the RR we are looking for must be signed with an
2296 * RRSIG. This is used for positive responses. */
2298 if (t
->scope
->dnssec_mode
== DNSSEC_NO
)
2301 if (dns_type_is_pseudo(rr
->key
->type
))
2304 r
= dns_transaction_negative_trust_anchor_lookup(t
, dns_resource_key_name(rr
->key
));
2310 switch (rr
->key
->type
) {
2312 case DNS_TYPE_RRSIG
:
2313 /* RRSIGs are the signatures themselves, they need no signing. */
2321 /* For SOA or NS RRs we look for a matching DS transaction */
2323 SET_FOREACH(dt
, t
->dnssec_transactions
, i
) {
2325 if (dt
->key
->class != rr
->key
->class)
2327 if (dt
->key
->type
!= DNS_TYPE_DS
)
2330 r
= dns_name_equal(dns_resource_key_name(dt
->key
), dns_resource_key_name(rr
->key
));
2336 /* We found a DS transactions for the SOA/NS
2337 * RRs we are looking at. If it discovered signed DS
2338 * RRs, then we need to be signed, too. */
2340 if (!dt
->answer_authenticated
)
2343 return dns_answer_match_key(dt
->answer
, dt
->key
, NULL
);
2346 /* We found nothing that proves this is safe to leave
2347 * this unauthenticated, hence ask inist on
2348 * authentication. */
2353 case DNS_TYPE_CNAME
:
2354 case DNS_TYPE_DNAME
: {
2355 const char *parent
= NULL
;
2360 * CNAME/DNAME RRs cannot be located at a zone apex, hence look directly for the parent SOA.
2362 * DS RRs are signed if the parent is signed, hence also look at the parent SOA
2365 SET_FOREACH(dt
, t
->dnssec_transactions
, i
) {
2367 if (dt
->key
->class != rr
->key
->class)
2369 if (dt
->key
->type
!= DNS_TYPE_SOA
)
2373 parent
= dns_resource_key_name(rr
->key
);
2374 r
= dns_name_parent(&parent
);
2378 if (rr
->key
->type
== DNS_TYPE_DS
)
2381 /* A CNAME/DNAME without a parent? That's sooo weird. */
2382 log_debug("Transaction %" PRIu16
" claims CNAME/DNAME at root. Refusing.", t
->id
);
2387 r
= dns_name_equal(dns_resource_key_name(dt
->key
), parent
);
2393 return t
->answer_authenticated
;
2403 /* Any other kind of RR (including DNSKEY/NSEC/NSEC3). Let's see if our SOA lookup was authenticated */
2405 SET_FOREACH(dt
, t
->dnssec_transactions
, i
) {
2407 if (dt
->key
->class != rr
->key
->class)
2409 if (dt
->key
->type
!= DNS_TYPE_SOA
)
2412 r
= dns_name_equal(dns_resource_key_name(dt
->key
), dns_resource_key_name(rr
->key
));
2418 /* We found the transaction that was supposed to find
2419 * the SOA RR for us. It was successful, but found no
2420 * RR for us. This means we are not at a zone cut. In
2421 * this case, we require authentication if the SOA
2422 * lookup was authenticated too. */
2423 return t
->answer_authenticated
;
2430 static int dns_transaction_in_private_tld(DnsTransaction
*t
, const DnsResourceKey
*key
) {
2436 /* If DNSSEC downgrade mode is on, checks whether the
2437 * specified RR is one level below a TLD we have proven not to
2438 * exist. In such a case we assume that this is a private
2439 * domain, and permit it.
2441 * This detects cases like the Fritz!Box router networks. Each
2442 * Fritz!Box router serves a private "fritz.box" zone, in the
2443 * non-existing TLD "box". Requests for the "fritz.box" domain
2444 * are served by the router itself, while requests for the
2445 * "box" domain will result in NXDOMAIN.
2447 * Note that this logic is unable to detect cases where a
2448 * router serves a private DNS zone directly under
2449 * non-existing TLD. In such a case we cannot detect whether
2450 * the TLD is supposed to exist or not, as all requests we
2451 * make for it will be answered by the router's zone, and not
2452 * by the root zone. */
2456 if (t
->scope
->dnssec_mode
!= DNSSEC_ALLOW_DOWNGRADE
)
2457 return false; /* In strict DNSSEC mode what doesn't exist, doesn't exist */
2459 tld
= dns_resource_key_name(key
);
2460 r
= dns_name_parent(&tld
);
2464 return false; /* Already the root domain */
2466 if (!dns_name_is_single_label(tld
))
2469 SET_FOREACH(dt
, t
->dnssec_transactions
, i
) {
2471 if (dt
->key
->class != key
->class)
2474 r
= dns_name_equal(dns_resource_key_name(dt
->key
), tld
);
2480 /* We found an auxiliary lookup we did for the TLD. If
2481 * that returned with NXDOMAIN, we know the TLD didn't
2482 * exist, and hence this might be a private zone. */
2484 return dt
->answer_rcode
== DNS_RCODE_NXDOMAIN
;
2490 static int dns_transaction_requires_nsec(DnsTransaction
*t
) {
2491 char key_str
[DNS_RESOURCE_KEY_STRING_MAX
];
2500 /* Checks if we need to insist on NSEC/NSEC3 RRs for proving
2501 * this negative reply */
2503 if (t
->scope
->dnssec_mode
== DNSSEC_NO
)
2506 if (dns_type_is_pseudo(t
->key
->type
))
2509 r
= dns_transaction_negative_trust_anchor_lookup(t
, dns_resource_key_name(t
->key
));
2515 r
= dns_transaction_in_private_tld(t
, t
->key
);
2519 /* The lookup is from a TLD that is proven not to
2520 * exist, and we are in downgrade mode, hence ignore
2521 * that fact that we didn't get any NSEC RRs. */
2523 log_info("Detected a negative query %s in a private DNS zone, permitting unsigned response.",
2524 dns_resource_key_to_string(t
->key
, key_str
, sizeof key_str
));
2528 name
= dns_resource_key_name(t
->key
);
2530 if (t
->key
->type
== DNS_TYPE_DS
) {
2532 /* We got a negative reply for this DS lookup? DS RRs are signed when their parent zone is signed,
2533 * hence check the parent SOA in this case. */
2535 r
= dns_name_parent(&name
);
2541 type
= DNS_TYPE_SOA
;
2543 } else if (IN_SET(t
->key
->type
, DNS_TYPE_SOA
, DNS_TYPE_NS
))
2544 /* We got a negative reply for this SOA/NS lookup? If so, check if there's a DS RR for this */
2547 /* For all other negative replies, check for the SOA lookup */
2548 type
= DNS_TYPE_SOA
;
2550 /* For all other RRs we check the SOA on the same level to see
2551 * if it's signed. */
2553 SET_FOREACH(dt
, t
->dnssec_transactions
, i
) {
2555 if (dt
->key
->class != t
->key
->class)
2557 if (dt
->key
->type
!= type
)
2560 r
= dns_name_equal(dns_resource_key_name(dt
->key
), name
);
2566 return dt
->answer_authenticated
;
2569 /* If in doubt, require NSEC/NSEC3 */
2573 static int dns_transaction_dnskey_authenticated(DnsTransaction
*t
, DnsResourceRecord
*rr
) {
2574 DnsResourceRecord
*rrsig
;
2578 /* Checks whether any of the DNSKEYs used for the RRSIGs for
2579 * the specified RRset is authenticated (i.e. has a matching
2582 r
= dns_transaction_negative_trust_anchor_lookup(t
, dns_resource_key_name(rr
->key
));
2588 DNS_ANSWER_FOREACH(rrsig
, t
->answer
) {
2592 r
= dnssec_key_match_rrsig(rr
->key
, rrsig
);
2598 SET_FOREACH(dt
, t
->dnssec_transactions
, i
) {
2600 if (dt
->key
->class != rr
->key
->class)
2603 if (dt
->key
->type
== DNS_TYPE_DNSKEY
) {
2605 r
= dns_name_equal(dns_resource_key_name(dt
->key
), rrsig
->rrsig
.signer
);
2611 /* OK, we found an auxiliary DNSKEY
2612 * lookup. If that lookup is
2613 * authenticated, report this. */
2615 if (dt
->answer_authenticated
)
2620 } else if (dt
->key
->type
== DNS_TYPE_DS
) {
2622 r
= dns_name_equal(dns_resource_key_name(dt
->key
), rrsig
->rrsig
.signer
);
2628 /* OK, we found an auxiliary DS
2629 * lookup. If that lookup is
2630 * authenticated and non-zero, we
2633 if (!dt
->answer_authenticated
)
2636 return dns_answer_match_key(dt
->answer
, dt
->key
, NULL
);
2641 return found
? false : -ENXIO
;
2644 static int dns_transaction_known_signed(DnsTransaction
*t
, DnsResourceRecord
*rr
) {
2648 /* We know that the root domain is signed, hence if it appears
2649 * not to be signed, there's a problem with the DNS server */
2651 return rr
->key
->class == DNS_CLASS_IN
&&
2652 dns_name_is_root(dns_resource_key_name(rr
->key
));
2655 static int dns_transaction_check_revoked_trust_anchors(DnsTransaction
*t
) {
2656 DnsResourceRecord
*rr
;
2661 /* Maybe warn the user that we encountered a revoked DNSKEY
2662 * for a key from our trust anchor. Note that we don't care
2663 * whether the DNSKEY can be authenticated or not. It's
2664 * sufficient if it is self-signed. */
2666 DNS_ANSWER_FOREACH(rr
, t
->answer
) {
2667 r
= dns_trust_anchor_check_revoked(&t
->scope
->manager
->trust_anchor
, rr
, t
->answer
);
2675 static int dns_transaction_invalidate_revoked_keys(DnsTransaction
*t
) {
2681 /* Removes all DNSKEY/DS objects from t->validated_keys that
2682 * our trust anchors database considers revoked. */
2685 DnsResourceRecord
*rr
;
2689 DNS_ANSWER_FOREACH(rr
, t
->validated_keys
) {
2690 r
= dns_trust_anchor_is_revoked(&t
->scope
->manager
->trust_anchor
, rr
);
2694 r
= dns_answer_remove_by_rr(&t
->validated_keys
, rr
);
2708 static int dns_transaction_copy_validated(DnsTransaction
*t
) {
2715 /* Copy all validated RRs from the auxiliary DNSSEC transactions into our set of validated RRs */
2717 SET_FOREACH(dt
, t
->dnssec_transactions
, i
) {
2719 if (DNS_TRANSACTION_IS_LIVE(dt
->state
))
2722 if (!dt
->answer_authenticated
)
2725 r
= dns_answer_extend(&t
->validated_keys
, dt
->answer
);
2734 DNSSEC_PHASE_DNSKEY
, /* Phase #1, only validate DNSKEYs */
2735 DNSSEC_PHASE_NSEC
, /* Phase #2, only validate NSEC+NSEC3 */
2736 DNSSEC_PHASE_ALL
, /* Phase #3, validate everything else */
2739 static int dnssec_validate_records(
2743 DnsAnswer
**validated
) {
2745 DnsResourceRecord
*rr
;
2748 /* Returns negative on error, 0 if validation failed, 1 to restart validation, 2 when finished. */
2750 DNS_ANSWER_FOREACH(rr
, t
->answer
) {
2751 DnsResourceRecord
*rrsig
= NULL
;
2752 DnssecResult result
;
2754 switch (rr
->key
->type
) {
2755 case DNS_TYPE_RRSIG
:
2758 case DNS_TYPE_DNSKEY
:
2759 /* We validate DNSKEYs only in the DNSKEY and ALL phases */
2760 if (phase
== DNSSEC_PHASE_NSEC
)
2765 case DNS_TYPE_NSEC3
:
2768 /* We validate NSEC/NSEC3 only in the NSEC and ALL phases */
2769 if (phase
== DNSSEC_PHASE_DNSKEY
)
2774 /* We validate all other RRs only in the ALL phases */
2775 if (phase
!= DNSSEC_PHASE_ALL
)
2779 r
= dnssec_verify_rrset_search(t
->answer
, rr
->key
, t
->validated_keys
, USEC_INFINITY
, &result
, &rrsig
);
2783 log_debug("Looking at %s: %s", strna(dns_resource_record_to_string(rr
)), dnssec_result_to_string(result
));
2785 if (result
== DNSSEC_VALIDATED
) {
2787 if (rr
->key
->type
== DNS_TYPE_DNSKEY
) {
2788 /* If we just validated a DNSKEY RRset, then let's add these keys to
2789 * the set of validated keys for this transaction. */
2791 r
= dns_answer_copy_by_key(&t
->validated_keys
, t
->answer
, rr
->key
, DNS_ANSWER_AUTHENTICATED
);
2795 /* Some of the DNSKEYs we just added might already have been revoked,
2796 * remove them again in that case. */
2797 r
= dns_transaction_invalidate_revoked_keys(t
);
2802 /* Add the validated RRset to the new list of validated
2803 * RRsets, and remove it from the unvalidated RRsets.
2804 * We mark the RRset as authenticated and cacheable. */
2805 r
= dns_answer_move_by_key(validated
, &t
->answer
, rr
->key
, DNS_ANSWER_AUTHENTICATED
|DNS_ANSWER_CACHEABLE
);
2809 manager_dnssec_verdict(t
->scope
->manager
, DNSSEC_SECURE
, rr
->key
);
2811 /* Exit the loop, we dropped something from the answer, start from the beginning */
2815 /* If we haven't read all DNSKEYs yet a negative result of the validation is irrelevant, as
2816 * there might be more DNSKEYs coming. Similar, if we haven't read all NSEC/NSEC3 RRs yet,
2817 * we cannot do positive wildcard proofs yet, as those require the NSEC/NSEC3 RRs. */
2818 if (phase
!= DNSSEC_PHASE_ALL
)
2821 if (result
== DNSSEC_VALIDATED_WILDCARD
) {
2822 bool authenticated
= false;
2825 /* This RRset validated, but as a wildcard. This means we need
2826 * to prove via NSEC/NSEC3 that no matching non-wildcard RR exists. */
2828 /* First step, determine the source of synthesis */
2829 r
= dns_resource_record_source(rrsig
, &source
);
2833 r
= dnssec_test_positive_wildcard(*validated
,
2834 dns_resource_key_name(rr
->key
),
2836 rrsig
->rrsig
.signer
,
2839 /* Unless the NSEC proof showed that the key really doesn't exist something is off. */
2841 result
= DNSSEC_INVALID
;
2843 r
= dns_answer_move_by_key(validated
, &t
->answer
, rr
->key
,
2844 authenticated
? (DNS_ANSWER_AUTHENTICATED
|DNS_ANSWER_CACHEABLE
) : 0);
2848 manager_dnssec_verdict(t
->scope
->manager
, authenticated
? DNSSEC_SECURE
: DNSSEC_INSECURE
, rr
->key
);
2850 /* Exit the loop, we dropped something from the answer, start from the beginning */
2855 if (result
== DNSSEC_NO_SIGNATURE
) {
2856 r
= dns_transaction_requires_rrsig(t
, rr
);
2860 /* Data does not require signing. In that case, just copy it over,
2861 * but remember that this is by no means authenticated. */
2862 r
= dns_answer_move_by_key(validated
, &t
->answer
, rr
->key
, 0);
2866 manager_dnssec_verdict(t
->scope
->manager
, DNSSEC_INSECURE
, rr
->key
);
2870 r
= dns_transaction_known_signed(t
, rr
);
2874 /* This is an RR we know has to be signed. If it isn't this means
2875 * the server is not attaching RRSIGs, hence complain. */
2877 dns_server_packet_rrsig_missing(t
->server
, t
->current_feature_level
);
2879 if (t
->scope
->dnssec_mode
== DNSSEC_ALLOW_DOWNGRADE
) {
2881 /* Downgrading is OK? If so, just consider the information unsigned */
2883 r
= dns_answer_move_by_key(validated
, &t
->answer
, rr
->key
, 0);
2887 manager_dnssec_verdict(t
->scope
->manager
, DNSSEC_INSECURE
, rr
->key
);
2891 /* Otherwise, fail */
2892 t
->answer_dnssec_result
= DNSSEC_INCOMPATIBLE_SERVER
;
2896 r
= dns_transaction_in_private_tld(t
, rr
->key
);
2900 char s
[DNS_RESOURCE_KEY_STRING_MAX
];
2902 /* The data is from a TLD that is proven not to exist, and we are in downgrade
2903 * mode, hence ignore the fact that this was not signed. */
2905 log_info("Detected RRset %s is in a private DNS zone, permitting unsigned RRs.",
2906 dns_resource_key_to_string(rr
->key
, s
, sizeof s
));
2908 r
= dns_answer_move_by_key(validated
, &t
->answer
, rr
->key
, 0);
2912 manager_dnssec_verdict(t
->scope
->manager
, DNSSEC_INSECURE
, rr
->key
);
2919 DNSSEC_SIGNATURE_EXPIRED
,
2920 DNSSEC_UNSUPPORTED_ALGORITHM
)) {
2922 r
= dns_transaction_dnskey_authenticated(t
, rr
);
2923 if (r
< 0 && r
!= -ENXIO
)
2926 /* The DNSKEY transaction was not authenticated, this means there's
2927 * no DS for this, which means it's OK if no keys are found for this signature. */
2929 r
= dns_answer_move_by_key(validated
, &t
->answer
, rr
->key
, 0);
2933 manager_dnssec_verdict(t
->scope
->manager
, DNSSEC_INSECURE
, rr
->key
);
2938 r
= dns_transaction_is_primary_response(t
, rr
);
2942 /* Look for a matching DNAME for this CNAME */
2943 r
= dns_answer_has_dname_for_cname(t
->answer
, rr
);
2947 /* Also look among the stuff we already validated */
2948 r
= dns_answer_has_dname_for_cname(*validated
, rr
);
2956 DNSSEC_SIGNATURE_EXPIRED
,
2957 DNSSEC_NO_SIGNATURE
))
2958 manager_dnssec_verdict(t
->scope
->manager
, DNSSEC_BOGUS
, rr
->key
);
2959 else /* DNSSEC_MISSING_KEY or DNSSEC_UNSUPPORTED_ALGORITHM */
2960 manager_dnssec_verdict(t
->scope
->manager
, DNSSEC_INDETERMINATE
, rr
->key
);
2962 /* This is a primary response to our question, and it failed validation.
2964 t
->answer_dnssec_result
= result
;
2968 /* This is a primary response, but we do have a DNAME RR
2969 * in the RR that can replay this CNAME, hence rely on
2970 * that, and we can remove the CNAME in favour of it. */
2973 /* This is just some auxiliary data. Just remove the RRset and continue. */
2974 r
= dns_answer_remove_by_key(&t
->answer
, rr
->key
);
2978 /* We dropped something from the answer, start from the beginning. */
2982 return 2; /* Finito. */
2985 int dns_transaction_validate_dnssec(DnsTransaction
*t
) {
2986 _cleanup_(dns_answer_unrefp
) DnsAnswer
*validated
= NULL
;
2988 DnsAnswerFlags flags
;
2990 char key_str
[DNS_RESOURCE_KEY_STRING_MAX
];
2994 /* We have now collected all DS and DNSKEY RRs in
2995 * t->validated_keys, let's see which RRs we can now
2996 * authenticate with that. */
2998 if (t
->scope
->dnssec_mode
== DNSSEC_NO
)
3001 /* Already validated */
3002 if (t
->answer_dnssec_result
!= _DNSSEC_RESULT_INVALID
)
3005 /* Our own stuff needs no validation */
3006 if (IN_SET(t
->answer_source
, DNS_TRANSACTION_ZONE
, DNS_TRANSACTION_TRUST_ANCHOR
)) {
3007 t
->answer_dnssec_result
= DNSSEC_VALIDATED
;
3008 t
->answer_authenticated
= true;
3012 /* Cached stuff is not affected by validation. */
3013 if (t
->answer_source
!= DNS_TRANSACTION_NETWORK
)
3016 if (!dns_transaction_dnssec_supported_full(t
)) {
3017 /* The server does not support DNSSEC, or doesn't augment responses with RRSIGs. */
3018 t
->answer_dnssec_result
= DNSSEC_INCOMPATIBLE_SERVER
;
3019 log_debug("Not validating response for %" PRIu16
", used server feature level does not support DNSSEC.", t
->id
);
3023 log_debug("Validating response from transaction %" PRIu16
" (%s).",
3025 dns_resource_key_to_string(t
->key
, key_str
, sizeof key_str
));
3027 /* First, see if this response contains any revoked trust
3028 * anchors we care about */
3029 r
= dns_transaction_check_revoked_trust_anchors(t
);
3033 /* Third, copy all RRs we acquired successfully from auxiliary RRs over. */
3034 r
= dns_transaction_copy_validated(t
);
3038 /* Second, see if there are DNSKEYs we already know a
3039 * validated DS for. */
3040 r
= dns_transaction_validate_dnskey_by_ds(t
);
3044 /* Fourth, remove all DNSKEY and DS RRs again that our trust
3045 * anchor says are revoked. After all we might have marked
3046 * some keys revoked above, but they might still be lingering
3047 * in our validated_keys list. */
3048 r
= dns_transaction_invalidate_revoked_keys(t
);
3052 phase
= DNSSEC_PHASE_DNSKEY
;
3054 bool have_nsec
= false;
3056 r
= dnssec_validate_records(t
, phase
, &have_nsec
, &validated
);
3060 /* Try again as long as we managed to achieve something */
3064 if (phase
== DNSSEC_PHASE_DNSKEY
&& have_nsec
) {
3065 /* OK, we processed all DNSKEYs, and there are NSEC/NSEC3 RRs, look at those now. */
3066 phase
= DNSSEC_PHASE_NSEC
;
3070 if (phase
!= DNSSEC_PHASE_ALL
) {
3071 /* OK, we processed all DNSKEYs and NSEC/NSEC3 RRs, look at all the rest now.
3072 * Note that in this third phase we start to remove RRs we couldn't validate. */
3073 phase
= DNSSEC_PHASE_ALL
;
3081 dns_answer_unref(t
->answer
);
3082 t
->answer
= validated
;
3085 /* At this point the answer only contains validated
3086 * RRsets. Now, let's see if it actually answers the question
3087 * we asked. If so, great! If it doesn't, then see if
3088 * NSEC/NSEC3 can prove this. */
3089 r
= dns_transaction_has_positive_answer(t
, &flags
);
3091 /* Yes, it answers the question! */
3093 if (flags
& DNS_ANSWER_AUTHENTICATED
) {
3094 /* The answer is fully authenticated, yay. */
3095 t
->answer_dnssec_result
= DNSSEC_VALIDATED
;
3096 t
->answer_rcode
= DNS_RCODE_SUCCESS
;
3097 t
->answer_authenticated
= true;
3099 /* The answer is not fully authenticated. */
3100 t
->answer_dnssec_result
= DNSSEC_UNSIGNED
;
3101 t
->answer_authenticated
= false;
3104 } else if (r
== 0) {
3105 DnssecNsecResult nr
;
3106 bool authenticated
= false;
3108 /* Bummer! Let's check NSEC/NSEC3 */
3109 r
= dnssec_nsec_test(t
->answer
, t
->key
, &nr
, &authenticated
, &t
->answer_nsec_ttl
);
3115 case DNSSEC_NSEC_NXDOMAIN
:
3116 /* NSEC proves the domain doesn't exist. Very good. */
3117 log_debug("Proved NXDOMAIN via NSEC/NSEC3 for transaction %u (%s)", t
->id
, key_str
);
3118 t
->answer_dnssec_result
= DNSSEC_VALIDATED
;
3119 t
->answer_rcode
= DNS_RCODE_NXDOMAIN
;
3120 t
->answer_authenticated
= authenticated
;
3122 manager_dnssec_verdict(t
->scope
->manager
, authenticated
? DNSSEC_SECURE
: DNSSEC_INSECURE
, t
->key
);
3125 case DNSSEC_NSEC_NODATA
:
3126 /* NSEC proves that there's no data here, very good. */
3127 log_debug("Proved NODATA via NSEC/NSEC3 for transaction %u (%s)", t
->id
, key_str
);
3128 t
->answer_dnssec_result
= DNSSEC_VALIDATED
;
3129 t
->answer_rcode
= DNS_RCODE_SUCCESS
;
3130 t
->answer_authenticated
= authenticated
;
3132 manager_dnssec_verdict(t
->scope
->manager
, authenticated
? DNSSEC_SECURE
: DNSSEC_INSECURE
, t
->key
);
3135 case DNSSEC_NSEC_OPTOUT
:
3136 /* NSEC3 says the data might not be signed */
3137 log_debug("Data is NSEC3 opt-out via NSEC/NSEC3 for transaction %u (%s)", t
->id
, key_str
);
3138 t
->answer_dnssec_result
= DNSSEC_UNSIGNED
;
3139 t
->answer_authenticated
= false;
3141 manager_dnssec_verdict(t
->scope
->manager
, DNSSEC_INSECURE
, t
->key
);
3144 case DNSSEC_NSEC_NO_RR
:
3145 /* No NSEC data? Bummer! */
3147 r
= dns_transaction_requires_nsec(t
);
3151 t
->answer_dnssec_result
= DNSSEC_NO_SIGNATURE
;
3152 manager_dnssec_verdict(t
->scope
->manager
, DNSSEC_BOGUS
, t
->key
);
3154 t
->answer_dnssec_result
= DNSSEC_UNSIGNED
;
3155 t
->answer_authenticated
= false;
3156 manager_dnssec_verdict(t
->scope
->manager
, DNSSEC_INSECURE
, t
->key
);
3161 case DNSSEC_NSEC_UNSUPPORTED_ALGORITHM
:
3162 /* We don't know the NSEC3 algorithm used? */
3163 t
->answer_dnssec_result
= DNSSEC_UNSUPPORTED_ALGORITHM
;
3164 manager_dnssec_verdict(t
->scope
->manager
, DNSSEC_INDETERMINATE
, t
->key
);
3167 case DNSSEC_NSEC_FOUND
:
3168 case DNSSEC_NSEC_CNAME
:
3169 /* NSEC says it needs to be there, but we couldn't find it? Bummer! */
3170 t
->answer_dnssec_result
= DNSSEC_NSEC_MISMATCH
;
3171 manager_dnssec_verdict(t
->scope
->manager
, DNSSEC_BOGUS
, t
->key
);
3175 assert_not_reached("Unexpected NSEC result.");
3182 static const char* const dns_transaction_state_table
[_DNS_TRANSACTION_STATE_MAX
] = {
3183 [DNS_TRANSACTION_NULL
] = "null",
3184 [DNS_TRANSACTION_PENDING
] = "pending",
3185 [DNS_TRANSACTION_VALIDATING
] = "validating",
3186 [DNS_TRANSACTION_RCODE_FAILURE
] = "rcode-failure",
3187 [DNS_TRANSACTION_SUCCESS
] = "success",
3188 [DNS_TRANSACTION_NO_SERVERS
] = "no-servers",
3189 [DNS_TRANSACTION_TIMEOUT
] = "timeout",
3190 [DNS_TRANSACTION_ATTEMPTS_MAX_REACHED
] = "attempts-max-reached",
3191 [DNS_TRANSACTION_INVALID_REPLY
] = "invalid-reply",
3192 [DNS_TRANSACTION_ERRNO
] = "errno",
3193 [DNS_TRANSACTION_ABORTED
] = "aborted",
3194 [DNS_TRANSACTION_DNSSEC_FAILED
] = "dnssec-failed",
3195 [DNS_TRANSACTION_NO_TRUST_ANCHOR
] = "no-trust-anchor",
3196 [DNS_TRANSACTION_RR_TYPE_UNSUPPORTED
] = "rr-type-unsupported",
3197 [DNS_TRANSACTION_NETWORK_DOWN
] = "network-down",
3198 [DNS_TRANSACTION_NOT_FOUND
] = "not-found",
3200 DEFINE_STRING_TABLE_LOOKUP(dns_transaction_state
, DnsTransactionState
);
3202 static const char* const dns_transaction_source_table
[_DNS_TRANSACTION_SOURCE_MAX
] = {
3203 [DNS_TRANSACTION_NETWORK
] = "network",
3204 [DNS_TRANSACTION_CACHE
] = "cache",
3205 [DNS_TRANSACTION_ZONE
] = "zone",
3206 [DNS_TRANSACTION_TRUST_ANCHOR
] = "trust-anchor",
3208 DEFINE_STRING_TABLE_LOOKUP(dns_transaction_source
, DnsTransactionSource
);