1 /* SPDX-License-Identifier: LGPL-2.1-or-later */
3 #include "sd-messages.h"
6 #include "alloc-util.h"
7 #include "dns-domain.h"
8 #include "errno-list.h"
9 #include "errno-util.h"
11 #include "glyph-util.h"
12 #include "random-util.h"
13 #include "resolved-dns-cache.h"
14 #include "resolved-dns-transaction.h"
15 #include "resolved-dnstls.h"
16 #include "resolved-llmnr.h"
17 #include "string-table.h"
19 #define TRANSACTIONS_MAX 4096
20 #define TRANSACTION_TCP_TIMEOUT_USEC (10U*USEC_PER_SEC)
22 /* After how much time to repeat classic DNS requests */
23 #define DNS_TIMEOUT_USEC (SD_RESOLVED_QUERY_TIMEOUT_USEC / DNS_TRANSACTION_ATTEMPTS_MAX)
25 static void dns_transaction_reset_answer(DnsTransaction
*t
) {
28 t
->received
= dns_packet_unref(t
->received
);
29 t
->answer
= dns_answer_unref(t
->answer
);
31 t
->answer_ede_rcode
= _DNS_EDE_RCODE_INVALID
;
32 t
->answer_ede_msg
= mfree(t
->answer_ede_msg
);
33 t
->answer_dnssec_result
= _DNSSEC_RESULT_INVALID
;
34 t
->answer_source
= _DNS_TRANSACTION_SOURCE_INVALID
;
35 t
->answer_query_flags
= 0;
36 t
->answer_nsec_ttl
= UINT32_MAX
;
40 static void dns_transaction_flush_dnssec_transactions(DnsTransaction
*t
) {
45 while ((z
= set_steal_first(t
->dnssec_transactions
))) {
46 set_remove(z
->notify_transactions
, t
);
47 set_remove(z
->notify_transactions_done
, t
);
48 dns_transaction_gc(z
);
52 static void dns_transaction_close_connection(
54 bool use_graveyard
) { /* Set use_graveyard = false when you know the connection is already
55 * dead, for example because you got a connection error back from the
56 * kernel. In that case there's no point in keeping the fd around,
63 /* Let's detach the stream from our transaction, in case something else keeps a reference to it. */
64 LIST_REMOVE(transactions_by_stream
, t
->stream
->transactions
, t
);
66 /* Remove packet in case it's still in the queue */
67 dns_packet_unref(ordered_set_remove(t
->stream
->write_queue
, t
->sent
));
69 t
->stream
= dns_stream_unref(t
->stream
);
72 t
->dns_udp_event_source
= sd_event_source_disable_unref(t
->dns_udp_event_source
);
74 /* If we have a UDP socket where we sent a packet, but never received one, then add it to the socket
75 * graveyard, instead of closing it right away. That way it will stick around for a moment longer,
76 * and the reply we might still get from the server will be eaten up instead of resulting in an ICMP
77 * port unreachable error message. */
79 /* Skip the graveyard stuff when we're shutting down, since that requires running event loop.
80 * Note that this is also called from dns_transaction_free(). In that case, scope may be NULL. */
83 !t
->scope
->manager
->event
||
84 sd_event_get_state(t
->scope
->manager
->event
) == SD_EVENT_FINISHED
)
85 use_graveyard
= false;
87 if (use_graveyard
&& t
->dns_udp_fd
>= 0 && t
->sent
&& !t
->received
) {
88 r
= manager_add_socket_to_graveyard(t
->scope
->manager
, t
->dns_udp_fd
);
90 log_debug_errno(r
, "Failed to add UDP socket to graveyard, closing immediately: %m");
92 TAKE_FD(t
->dns_udp_fd
);
95 t
->dns_udp_fd
= safe_close(t
->dns_udp_fd
);
98 static void dns_transaction_stop_timeout(DnsTransaction
*t
) {
101 t
->timeout_event_source
= sd_event_source_disable_unref(t
->timeout_event_source
);
104 DnsTransaction
* dns_transaction_free(DnsTransaction
*t
) {
105 DnsQueryCandidate
*c
;
112 log_debug("Freeing transaction %" PRIu16
".", t
->id
);
114 dns_transaction_close_connection(t
, true);
115 dns_transaction_stop_timeout(t
);
117 dns_packet_unref(t
->sent
);
118 dns_transaction_reset_answer(t
);
120 dns_server_unref(t
->server
);
124 DnsTransaction
*first
;
126 first
= hashmap_get(t
->scope
->transactions_by_key
, t
->key
);
127 LIST_REMOVE(transactions_by_key
, first
, t
);
129 hashmap_replace(t
->scope
->transactions_by_key
, first
->key
, first
);
131 hashmap_remove(t
->scope
->transactions_by_key
, t
->key
);
134 LIST_REMOVE(transactions_by_scope
, t
->scope
->transactions
, t
);
137 hashmap_remove(t
->scope
->manager
->dns_transactions
, UINT_TO_PTR(t
->id
));
140 while ((c
= set_steal_first(t
->notify_query_candidates
)))
141 set_remove(c
->transactions
, t
);
142 set_free(t
->notify_query_candidates
);
144 while ((c
= set_steal_first(t
->notify_query_candidates_done
)))
145 set_remove(c
->transactions
, t
);
146 set_free(t
->notify_query_candidates_done
);
148 while ((i
= set_steal_first(t
->notify_zone_items
)))
149 i
->probe_transaction
= NULL
;
150 set_free(t
->notify_zone_items
);
152 while ((i
= set_steal_first(t
->notify_zone_items_done
)))
153 i
->probe_transaction
= NULL
;
154 set_free(t
->notify_zone_items_done
);
156 while ((z
= set_steal_first(t
->notify_transactions
)))
157 set_remove(z
->dnssec_transactions
, t
);
158 set_free(t
->notify_transactions
);
160 while ((z
= set_steal_first(t
->notify_transactions_done
)))
161 set_remove(z
->dnssec_transactions
, t
);
162 set_free(t
->notify_transactions_done
);
164 dns_transaction_flush_dnssec_transactions(t
);
165 set_free(t
->dnssec_transactions
);
167 dns_answer_unref(t
->validated_keys
);
168 dns_resource_key_unref(t
->key
);
169 dns_packet_unref(t
->bypass
);
174 DEFINE_TRIVIAL_CLEANUP_FUNC(DnsTransaction
*, dns_transaction_free
);
176 DnsTransaction
* dns_transaction_gc(DnsTransaction
*t
) {
179 /* Returns !NULL if we can't gc yet. */
184 if (t
->wait_for_answer
&& IN_SET(t
->state
, DNS_TRANSACTION_PENDING
, DNS_TRANSACTION_VALIDATING
))
187 if (set_isempty(t
->notify_query_candidates
) &&
188 set_isempty(t
->notify_query_candidates_done
) &&
189 set_isempty(t
->notify_zone_items
) &&
190 set_isempty(t
->notify_zone_items_done
) &&
191 set_isempty(t
->notify_transactions
) &&
192 set_isempty(t
->notify_transactions_done
))
193 return dns_transaction_free(t
);
198 static uint16_t pick_new_id(Manager
*m
) {
201 /* Find a fresh, unused transaction id. Note that this loop is bounded because there's a limit on the
202 * number of transactions, and it's much lower than the space of IDs. */
204 assert_cc(TRANSACTIONS_MAX
< 0xFFFF);
207 random_bytes(&new_id
, sizeof(new_id
));
208 while (new_id
== 0 ||
209 hashmap_get(m
->dns_transactions
, UINT_TO_PTR(new_id
)));
216 DnsResourceKey
*key
) {
218 /* Don't allow looking up invalid or pseudo RRs */
219 if (!dns_type_is_valid_query(key
->type
))
221 if (dns_type_is_obsolete(key
->type
))
224 /* We only support the IN class */
225 if (!IN_SET(key
->class, DNS_CLASS_IN
, DNS_CLASS_ANY
))
228 /* Don't allows DNSSEC RRs to be looked up via LLMNR/mDNS. They don't really make sense
229 * there, and it speeds up our queries if we refuse this early */
230 if (scope
->protocol
!= DNS_PROTOCOL_DNS
&&
231 dns_type_is_dnssec(key
->type
))
237 int dns_transaction_new(
238 DnsTransaction
**ret
,
242 uint64_t query_flags
) {
244 _cleanup_(dns_transaction_freep
) DnsTransaction
*t
= NULL
;
260 r
= dns_packet_validate_query(bypass
);
264 DNS_QUESTION_FOREACH(qk
, bypass
->question
) {
271 if (hashmap_size(s
->manager
->dns_transactions
) >= TRANSACTIONS_MAX
)
274 r
= hashmap_ensure_allocated(&s
->manager
->dns_transactions
, NULL
);
279 r
= hashmap_ensure_allocated(&s
->transactions_by_key
, &dns_resource_key_hash_ops
);
284 t
= new(DnsTransaction
, 1);
288 *t
= (DnsTransaction
) {
289 .dns_udp_fd
= -EBADF
,
290 .answer_source
= _DNS_TRANSACTION_SOURCE_INVALID
,
291 .answer_dnssec_result
= _DNSSEC_RESULT_INVALID
,
292 .answer_ede_rcode
= _DNS_EDE_RCODE_INVALID
,
293 .answer_nsec_ttl
= UINT32_MAX
,
294 .key
= dns_resource_key_ref(key
),
295 .query_flags
= query_flags
,
296 .bypass
= dns_packet_ref(bypass
),
297 .current_feature_level
= _DNS_SERVER_FEATURE_LEVEL_INVALID
,
298 .clamp_feature_level_servfail
= _DNS_SERVER_FEATURE_LEVEL_INVALID
,
299 .id
= pick_new_id(s
->manager
),
302 r
= hashmap_put(s
->manager
->dns_transactions
, UINT_TO_PTR(t
->id
), t
);
309 DnsTransaction
*first
;
311 first
= hashmap_get(s
->transactions_by_key
, t
->key
);
312 LIST_PREPEND(transactions_by_key
, first
, t
);
314 r
= hashmap_replace(s
->transactions_by_key
, first
->key
, first
);
316 LIST_REMOVE(transactions_by_key
, first
, t
);
321 LIST_PREPEND(transactions_by_scope
, s
->transactions
, t
);
324 s
->manager
->n_transactions_total
++;
333 static void dns_transaction_shuffle_id(DnsTransaction
*t
) {
337 /* Pick a new ID for this transaction. */
339 new_id
= pick_new_id(t
->scope
->manager
);
340 assert_se(hashmap_remove_and_put(t
->scope
->manager
->dns_transactions
, UINT_TO_PTR(t
->id
), UINT_TO_PTR(new_id
), t
) >= 0);
342 log_debug("Transaction %" PRIu16
" is now %" PRIu16
".", t
->id
, new_id
);
345 /* Make sure we generate a new packet with the new ID */
346 t
->sent
= dns_packet_unref(t
->sent
);
349 static void dns_transaction_tentative(DnsTransaction
*t
, DnsPacket
*p
) {
350 char key_str
[DNS_RESOURCE_KEY_STRING_MAX
];
355 assert(t
->scope
->protocol
== DNS_PROTOCOL_LLMNR
);
357 if (manager_packet_from_local_address(t
->scope
->manager
, p
) != 0)
360 log_debug("Transaction %" PRIu16
" for <%s> on scope %s on %s/%s got tentative packet from %s.",
362 dns_resource_key_to_string(dns_transaction_key(t
), key_str
, sizeof key_str
),
363 dns_protocol_to_string(t
->scope
->protocol
),
364 t
->scope
->link
? t
->scope
->link
->ifname
: "*",
365 af_to_name_short(t
->scope
->family
),
366 IN_ADDR_TO_STRING(p
->family
, &p
->sender
));
368 /* RFC 4795, Section 4.1 says that the peer with the
369 * lexicographically smaller IP address loses */
370 if (memcmp(&p
->sender
, &p
->destination
, FAMILY_ADDRESS_SIZE(p
->family
)) >= 0) {
371 log_debug("Peer has lexicographically larger IP address and thus lost in the conflict.");
375 log_debug("We have the lexicographically larger IP address and thus lost in the conflict.");
379 while ((z
= set_first(t
->notify_zone_items
))) {
380 /* First, make sure the zone item drops the reference
382 dns_zone_item_probe_stop(z
);
384 /* Secondly, report this as conflict, so that we might
385 * look for a different hostname */
386 dns_zone_item_conflict(z
);
390 dns_transaction_gc(t
);
393 void dns_transaction_complete(DnsTransaction
*t
, DnsTransactionState state
) {
394 DnsQueryCandidate
*c
;
398 char key_str
[DNS_RESOURCE_KEY_STRING_MAX
];
401 assert(!DNS_TRANSACTION_IS_LIVE(state
));
403 if (state
== DNS_TRANSACTION_DNSSEC_FAILED
) {
404 dns_resource_key_to_string(dns_transaction_key(t
), key_str
, sizeof key_str
);
406 log_struct(LOG_NOTICE
,
407 "MESSAGE_ID=" SD_MESSAGE_DNSSEC_FAILURE_STR
,
408 LOG_MESSAGE("DNSSEC validation failed for question %s: %s",
409 key_str
, dnssec_result_to_string(t
->answer_dnssec_result
)),
410 "DNS_TRANSACTION=%" PRIu16
, t
->id
,
411 "DNS_QUESTION=%s", key_str
,
412 "DNSSEC_RESULT=%s", dnssec_result_to_string(t
->answer_dnssec_result
),
413 "DNS_SERVER=%s", strna(dns_server_string_full(t
->server
)),
414 "DNS_SERVER_FEATURE_LEVEL=%s", dns_server_feature_level_to_string(t
->server
->possible_feature_level
));
417 /* Note that this call might invalidate the query. Callers
418 * should hence not attempt to access the query or transaction
419 * after calling this function. */
421 if (state
== DNS_TRANSACTION_ERRNO
)
422 st
= errno_to_name(t
->answer_errno
);
424 st
= dns_transaction_state_to_string(state
);
426 log_debug("%s transaction %" PRIu16
" for <%s> on scope %s on %s/%s now complete with <%s> from %s (%s; %s).",
427 t
->bypass
? "Bypass" : "Regular",
429 dns_resource_key_to_string(dns_transaction_key(t
), key_str
, sizeof key_str
),
430 dns_protocol_to_string(t
->scope
->protocol
),
431 t
->scope
->link
? t
->scope
->link
->ifname
: "*",
432 af_to_name_short(t
->scope
->family
),
434 t
->answer_source
< 0 ? "none" : dns_transaction_source_to_string(t
->answer_source
),
435 FLAGS_SET(t
->query_flags
, SD_RESOLVED_NO_VALIDATE
) ? "not validated" :
436 (FLAGS_SET(t
->answer_query_flags
, SD_RESOLVED_AUTHENTICATED
) ? "authenticated" : "unsigned"),
437 FLAGS_SET(t
->answer_query_flags
, SD_RESOLVED_CONFIDENTIAL
) ? "confidential" : "non-confidential");
441 dns_transaction_close_connection(t
, true);
442 dns_transaction_stop_timeout(t
);
444 /* Notify all queries that are interested, but make sure the
445 * transaction isn't freed while we are still looking at it */
448 SET_FOREACH_MOVE(c
, t
->notify_query_candidates_done
, t
->notify_query_candidates
)
449 dns_query_candidate_notify(c
);
450 SWAP_TWO(t
->notify_query_candidates
, t
->notify_query_candidates_done
);
452 SET_FOREACH_MOVE(z
, t
->notify_zone_items_done
, t
->notify_zone_items
)
453 dns_zone_item_notify(z
);
454 SWAP_TWO(t
->notify_zone_items
, t
->notify_zone_items_done
);
455 if (t
->probing
&& t
->state
== DNS_TRANSACTION_ATTEMPTS_MAX_REACHED
)
456 (void) dns_scope_announce(t
->scope
, false);
458 SET_FOREACH_MOVE(d
, t
->notify_transactions_done
, t
->notify_transactions
)
459 dns_transaction_notify(d
, t
);
460 SWAP_TWO(t
->notify_transactions
, t
->notify_transactions_done
);
463 dns_transaction_gc(t
);
466 static void dns_transaction_complete_errno(DnsTransaction
*t
, int error
) {
470 t
->answer_errno
= abs(error
);
471 dns_transaction_complete(t
, DNS_TRANSACTION_ERRNO
);
474 static int dns_transaction_pick_server(DnsTransaction
*t
) {
478 assert(t
->scope
->protocol
== DNS_PROTOCOL_DNS
);
480 /* Pick a DNS server and a feature level for it. */
482 server
= dns_scope_get_dns_server(t
->scope
);
486 /* If we changed the server invalidate the feature level clamping, as the new server might have completely
487 * different properties. */
488 if (server
!= t
->server
)
489 t
->clamp_feature_level_servfail
= _DNS_SERVER_FEATURE_LEVEL_INVALID
;
491 t
->current_feature_level
= dns_server_possible_feature_level(server
);
493 /* Clamp the feature level if that is requested. */
494 if (t
->clamp_feature_level_servfail
!= _DNS_SERVER_FEATURE_LEVEL_INVALID
&&
495 t
->current_feature_level
> t
->clamp_feature_level_servfail
)
496 t
->current_feature_level
= t
->clamp_feature_level_servfail
;
498 log_debug("Using feature level %s for transaction %u.", dns_server_feature_level_to_string(t
->current_feature_level
), t
->id
);
500 if (server
== t
->server
)
503 dns_server_unref(t
->server
);
504 t
->server
= dns_server_ref(server
);
506 t
->n_picked_servers
++;
508 log_debug("Using DNS server %s for transaction %u.", strna(dns_server_string_full(t
->server
)), t
->id
);
513 static void dns_transaction_retry(DnsTransaction
*t
, bool next_server
) {
518 /* Retries the transaction as it is, possibly on a different server */
520 if (next_server
&& t
->scope
->protocol
== DNS_PROTOCOL_DNS
)
521 log_debug("Retrying transaction %" PRIu16
", after switching servers.", t
->id
);
523 log_debug("Retrying transaction %" PRIu16
".", t
->id
);
525 /* Before we try again, switch to a new server. */
527 dns_scope_next_dns_server(t
->scope
, t
->server
);
529 r
= dns_transaction_go(t
);
531 dns_transaction_complete_errno(t
, r
);
534 static bool dns_transaction_limited_retry(DnsTransaction
*t
) {
537 /* If we haven't tried all different servers yet, let's try again with a different server */
539 if (t
->n_picked_servers
>= dns_scope_get_n_dns_servers(t
->scope
))
542 dns_transaction_retry(t
, /* next_server= */ true);
546 static int dns_transaction_maybe_restart(DnsTransaction
*t
) {
551 /* Restarts the transaction, under a new ID if the feature level of the server changed since we first
552 * tried, without changing DNS server. Returns > 0 if the transaction was restarted, 0 if not. */
557 if (t
->current_feature_level
<= dns_server_possible_feature_level(t
->server
))
560 /* The server's current feature level is lower than when we sent the original query. We learnt something from
561 the response or possibly an auxiliary DNSSEC response that we didn't know before. We take that as reason to
562 restart the whole transaction. This is a good idea to deal with servers that respond rubbish if we include
563 OPT RR or DO bit. One of these cases is documented here, for example:
564 https://open.nlnetlabs.nl/pipermail/dnssec-trigger/2014-November/000376.html */
566 log_debug("Server feature level is now lower than when we began our transaction. Restarting with new ID.");
567 dns_transaction_shuffle_id(t
);
569 r
= dns_transaction_go(t
);
576 static void on_transaction_stream_error(DnsTransaction
*t
, int error
) {
579 dns_transaction_close_connection(t
, true);
581 if (ERRNO_IS_DISCONNECT(error
)) {
582 if (t
->scope
->protocol
== DNS_PROTOCOL_LLMNR
) {
583 /* If the LLMNR/TCP connection failed, the host doesn't support LLMNR, and we cannot answer the
584 * question on this scope. */
585 dns_transaction_complete(t
, DNS_TRANSACTION_NOT_FOUND
);
589 dns_transaction_retry(t
, true);
593 dns_transaction_complete_errno(t
, error
);
596 static int dns_transaction_on_stream_packet(DnsTransaction
*t
, DnsStream
*s
, DnsPacket
*p
) {
603 encrypted
= s
->encrypted
;
605 dns_transaction_close_connection(t
, true);
607 if (dns_packet_validate_reply(p
) <= 0) {
608 log_debug("Invalid TCP reply packet.");
609 dns_transaction_complete(t
, DNS_TRANSACTION_INVALID_REPLY
);
613 dns_scope_check_conflicts(t
->scope
, p
);
616 dns_transaction_process_reply(t
, p
, encrypted
);
619 /* If the response wasn't useful, then complete the transition
620 * now. After all, we are the worst feature set now with TCP
621 * sockets, and there's really no point in retrying. */
622 if (t
->state
== DNS_TRANSACTION_PENDING
)
623 dns_transaction_complete(t
, DNS_TRANSACTION_INVALID_REPLY
);
625 dns_transaction_gc(t
);
630 static int on_stream_complete(DnsStream
*s
, int error
) {
633 if (ERRNO_IS_DISCONNECT(error
) && s
->protocol
!= DNS_PROTOCOL_LLMNR
) {
634 log_debug_errno(error
, "Connection failure for DNS TCP stream: %m");
636 if (s
->transactions
) {
640 dns_server_packet_lost(t
->server
, IPPROTO_TCP
, t
->current_feature_level
);
645 /* First, detach the stream from the server. Otherwise, transactions attached to this stream
646 * may be restarted by on_transaction_stream_error() below with this stream. */
647 dns_stream_detach(s
);
649 /* Do not use LIST_FOREACH() here, as
650 * on_transaction_stream_error()
651 * -> dns_transaction_complete_errno()
652 * -> dns_transaction_free()
653 * may free multiple transactions in the list. */
655 while ((t
= s
->transactions
))
656 on_transaction_stream_error(t
, error
);
662 static int on_stream_packet(DnsStream
*s
, DnsPacket
*p
) {
669 t
= hashmap_get(s
->manager
->dns_transactions
, UINT_TO_PTR(DNS_PACKET_ID(p
)));
670 if (t
&& t
->stream
== s
) /* Validate that the stream we got this on actually is the stream the
671 * transaction was using. */
672 return dns_transaction_on_stream_packet(t
, s
, p
);
674 /* Ignore incorrect transaction id as an old transaction can have been canceled. */
675 log_debug("Received unexpected TCP reply packet with id %" PRIu16
", ignoring.", DNS_PACKET_ID(p
));
679 static uint16_t dns_transaction_port(DnsTransaction
*t
) {
682 if (t
->server
->port
> 0)
683 return t
->server
->port
;
685 return DNS_SERVER_FEATURE_LEVEL_IS_TLS(t
->current_feature_level
) ? 853 : 53;
688 static int dns_transaction_emit_tcp(DnsTransaction
*t
) {
689 usec_t stream_timeout_usec
= DNS_STREAM_DEFAULT_TIMEOUT_USEC
;
690 _cleanup_(dns_stream_unrefp
) DnsStream
*s
= NULL
;
691 _cleanup_close_
int fd
= -EBADF
;
692 union sockaddr_union sa
;
699 dns_transaction_close_connection(t
, true);
701 switch (t
->scope
->protocol
) {
703 case DNS_PROTOCOL_DNS
:
704 r
= dns_transaction_pick_server(t
);
708 if (manager_server_is_stub(t
->scope
->manager
, t
->server
))
712 if (!dns_server_dnssec_supported(t
->server
) && dns_type_is_dnssec(dns_transaction_key(t
)->type
))
715 r
= dns_server_adjust_opt(t
->server
, t
->sent
, t
->current_feature_level
);
720 if (t
->server
->stream
&& (DNS_SERVER_FEATURE_LEVEL_IS_TLS(t
->current_feature_level
) == t
->server
->stream
->encrypted
))
721 s
= dns_stream_ref(t
->server
->stream
);
723 fd
= dns_scope_socket_tcp(t
->scope
, AF_UNSPEC
, NULL
, t
->server
, dns_transaction_port(t
), &sa
);
725 /* Lower timeout in DNS-over-TLS opportunistic mode. In environments where DoT is blocked
726 * without ICMP response overly long delays when contacting DoT servers are nasty, in
727 * particular if multiple DNS servers are defined which we try in turn and all are
728 * blocked. Hence, substantially lower the timeout in that case. */
729 if (DNS_SERVER_FEATURE_LEVEL_IS_TLS(t
->current_feature_level
) &&
730 dns_server_get_dns_over_tls_mode(t
->server
) == DNS_OVER_TLS_OPPORTUNISTIC
)
731 stream_timeout_usec
= DNS_STREAM_OPPORTUNISTIC_TLS_TIMEOUT_USEC
;
733 type
= DNS_STREAM_LOOKUP
;
736 case DNS_PROTOCOL_LLMNR
:
737 /* When we already received a reply to this (but it was truncated), send to its sender address */
739 fd
= dns_scope_socket_tcp(t
->scope
, t
->received
->family
, &t
->received
->sender
, NULL
, t
->received
->sender_port
, &sa
);
741 union in_addr_union address
;
742 int family
= AF_UNSPEC
;
744 /* Otherwise, try to talk to the owner of a
745 * the IP address, in case this is a reverse
748 r
= dns_name_address(dns_resource_key_name(dns_transaction_key(t
)), &family
, &address
);
753 if (family
!= t
->scope
->family
)
756 fd
= dns_scope_socket_tcp(t
->scope
, family
, &address
, NULL
, LLMNR_PORT
, &sa
);
759 type
= DNS_STREAM_LLMNR_SEND
;
763 return -EAFNOSUPPORT
;
770 r
= dns_stream_new(t
->scope
->manager
, &s
, type
, t
->scope
->protocol
, fd
, &sa
,
771 on_stream_packet
, on_stream_complete
, stream_timeout_usec
);
777 #if ENABLE_DNS_OVER_TLS
778 if (t
->scope
->protocol
== DNS_PROTOCOL_DNS
&&
779 DNS_SERVER_FEATURE_LEVEL_IS_TLS(t
->current_feature_level
)) {
782 r
= dnstls_stream_connect_tls(s
, t
->server
);
789 dns_server_unref_stream(t
->server
);
790 s
->server
= dns_server_ref(t
->server
);
791 t
->server
->stream
= dns_stream_ref(s
);
794 /* The interface index is difficult to determine if we are
795 * connecting to the local host, hence fill this in right away
796 * instead of determining it from the socket */
797 s
->ifindex
= dns_scope_ifindex(t
->scope
);
800 t
->stream
= TAKE_PTR(s
);
801 LIST_PREPEND(transactions_by_stream
, t
->stream
->transactions
, t
);
803 r
= dns_stream_write_packet(t
->stream
, t
->sent
);
805 dns_transaction_close_connection(t
, /* use_graveyard= */ false);
809 dns_transaction_reset_answer(t
);
811 t
->tried_stream
= true;
816 static void dns_transaction_cache_answer(DnsTransaction
*t
) {
819 /* For mDNS we cache whenever we get the packet, rather than
820 * in each transaction. */
821 if (!IN_SET(t
->scope
->protocol
, DNS_PROTOCOL_DNS
, DNS_PROTOCOL_LLMNR
))
824 /* Caching disabled? */
825 if (t
->scope
->manager
->enable_cache
== DNS_CACHE_MODE_NO
)
828 /* If validation is turned off for this transaction, but DNSSEC is on, then let's not cache this */
829 if (FLAGS_SET(t
->query_flags
, SD_RESOLVED_NO_VALIDATE
) && t
->scope
->dnssec_mode
!= DNSSEC_NO
)
832 /* Packet from localhost? */
833 if (!t
->scope
->manager
->cache_from_localhost
&&
834 in_addr_is_localhost(t
->received
->family
, &t
->received
->sender
) != 0)
837 dns_cache_put(&t
->scope
->cache
,
838 t
->scope
->manager
->enable_cache
,
840 dns_transaction_key(t
),
843 DNS_PACKET_CD(t
->received
) ? t
->received
: NULL
, /* only cache full packets with CD on,
844 * since our use case for caching them
845 * is "bypass" mode which is only
846 * enabled for CD packets. */
847 t
->answer_query_flags
,
848 t
->answer_dnssec_result
,
851 &t
->received
->sender
,
852 t
->scope
->manager
->stale_retention_usec
);
855 static bool dns_transaction_dnssec_is_live(DnsTransaction
*t
) {
860 SET_FOREACH(dt
, t
->dnssec_transactions
)
861 if (DNS_TRANSACTION_IS_LIVE(dt
->state
))
867 static int dns_transaction_dnssec_ready(DnsTransaction
*t
) {
873 /* Checks whether the auxiliary DNSSEC transactions of our transaction have completed, or are still
874 * ongoing. Returns 0, if we aren't ready for the DNSSEC validation, positive if we are. */
876 SET_FOREACH(dt
, t
->dnssec_transactions
) {
880 case DNS_TRANSACTION_NULL
:
881 case DNS_TRANSACTION_PENDING
:
882 case DNS_TRANSACTION_VALIDATING
:
886 case DNS_TRANSACTION_RCODE_FAILURE
:
887 if (!IN_SET(dt
->answer_rcode
, DNS_RCODE_NXDOMAIN
, DNS_RCODE_SERVFAIL
)) {
888 log_debug("Auxiliary DNSSEC RR query failed with rcode=%s.", FORMAT_DNS_RCODE(dt
->answer_rcode
));
892 /* Fall-through: NXDOMAIN/SERVFAIL is good enough for us. This is because some DNS servers
893 * erroneously return NXDOMAIN/SERVFAIL for empty non-terminals (Akamai...) or missing DS
894 * records (Facebook), and we need to handle that nicely, when asking for parent SOA or similar
895 * RRs to make unsigned proofs. */
897 case DNS_TRANSACTION_SUCCESS
:
901 case DNS_TRANSACTION_DNSSEC_FAILED
:
902 /* We handle DNSSEC failures different from other errors, as we care about the DNSSEC
903 * validation result */
905 log_debug("Auxiliary DNSSEC RR query failed validation: %s%s%s%s%s%s",
906 dnssec_result_to_string(dt
->answer_dnssec_result
),
907 dt
->answer_ede_rcode
>= 0 ? " (" : "",
908 dt
->answer_ede_rcode
>= 0 ? FORMAT_DNS_EDE_RCODE(dt
->answer_ede_rcode
) : "",
909 (dt
->answer_ede_rcode
>= 0 && !isempty(dt
->answer_ede_msg
)) ? ": " : "",
910 dt
->answer_ede_rcode
>= 0 ? strempty(dt
->answer_ede_msg
) : "",
911 dt
->answer_ede_rcode
>= 0 ? ")" : "");
913 /* Copy error code over */
914 t
->answer_dnssec_result
= dt
->answer_dnssec_result
;
915 t
->answer_ede_rcode
= dt
->answer_ede_rcode
;
916 r
= free_and_strdup(&t
->answer_ede_msg
, dt
->answer_ede_msg
);
920 dns_transaction_complete(t
, DNS_TRANSACTION_DNSSEC_FAILED
);
924 log_debug("Auxiliary DNSSEC RR query failed with %s", dns_transaction_state_to_string(dt
->state
));
929 /* All is ready, we can go and validate */
933 /* Some auxiliary DNSSEC transaction failed for some reason. Maybe we learned something about the
934 * server due to this failure, and the feature level is now different? Let's see and restart the
935 * transaction if so. If not, let's propagate the auxiliary failure.
937 * This is particularly relevant if an auxiliary request figured out that DNSSEC doesn't work, and we
938 * are in permissive DNSSEC mode, and thus should restart things without DNSSEC magic. */
939 r
= dns_transaction_maybe_restart(t
);
943 return 0; /* don't validate just yet, we restarted things */
945 t
->answer_dnssec_result
= DNSSEC_FAILED_AUXILIARY
;
946 dns_transaction_complete(t
, DNS_TRANSACTION_DNSSEC_FAILED
);
950 static void dns_transaction_process_dnssec(DnsTransaction
*t
) {
955 /* Are there ongoing DNSSEC transactions? If so, let's wait for them. */
956 r
= dns_transaction_dnssec_ready(t
);
959 if (r
== 0) /* We aren't ready yet (or one of our auxiliary transactions failed, and we shouldn't validate now */
962 /* See if we learnt things from the additional DNSSEC transactions, that we didn't know before, and better
963 * restart the lookup immediately. */
964 r
= dns_transaction_maybe_restart(t
);
967 if (r
> 0) /* Transaction got restarted... */
970 /* All our auxiliary DNSSEC transactions are complete now. Try
971 * to validate our RRset now. */
972 r
= dns_transaction_validate_dnssec(t
);
974 dns_transaction_complete(t
, DNS_TRANSACTION_INVALID_REPLY
);
980 if (t
->answer_dnssec_result
== DNSSEC_INCOMPATIBLE_SERVER
&&
981 t
->scope
->dnssec_mode
== DNSSEC_YES
) {
983 /* We are not in automatic downgrade mode, and the server is bad. Let's try a different server, maybe
986 if (dns_transaction_limited_retry(t
))
989 /* OK, let's give up, apparently all servers we tried didn't work. */
990 dns_transaction_complete(t
, DNS_TRANSACTION_DNSSEC_FAILED
);
994 if (!IN_SET(t
->answer_dnssec_result
,
995 _DNSSEC_RESULT_INVALID
, /* No DNSSEC validation enabled */
996 DNSSEC_VALIDATED
, /* Answer is signed and validated successfully */
997 DNSSEC_UNSIGNED
, /* Answer is right-fully unsigned */
998 DNSSEC_INCOMPATIBLE_SERVER
)) { /* Server does not do DNSSEC (Yay, we are downgrade attack vulnerable!) */
999 dns_transaction_complete(t
, DNS_TRANSACTION_DNSSEC_FAILED
);
1003 if (t
->answer_dnssec_result
== DNSSEC_INCOMPATIBLE_SERVER
)
1004 dns_server_warn_downgrade(t
->server
);
1006 dns_transaction_cache_answer(t
);
1008 if (t
->answer_rcode
== DNS_RCODE_SUCCESS
)
1009 dns_transaction_complete(t
, DNS_TRANSACTION_SUCCESS
);
1011 dns_transaction_complete(t
, DNS_TRANSACTION_RCODE_FAILURE
);
1016 dns_transaction_complete_errno(t
, r
);
1019 static int dns_transaction_has_positive_answer(DnsTransaction
*t
, DnsAnswerFlags
*flags
) {
1024 /* Checks whether the answer is positive, i.e. either a direct
1025 * answer to the question, or a CNAME/DNAME for it */
1027 r
= dns_answer_match_key(t
->answer
, dns_transaction_key(t
), flags
);
1031 r
= dns_answer_find_cname_or_dname(t
->answer
, dns_transaction_key(t
), NULL
, flags
);
1038 static int dns_transaction_fix_rcode(DnsTransaction
*t
) {
1043 /* Fix up the RCODE to SUCCESS if we get at least one matching RR in a response. Note that this contradicts the
1044 * DNS RFCs a bit. Specifically, RFC 6604 Section 3 clarifies that the RCODE shall say something about a
1045 * CNAME/DNAME chain element coming after the last chain element contained in the message, and not the first
1046 * one included. However, it also indicates that not all DNS servers implement this correctly. Moreover, when
1047 * using DNSSEC we usually only can prove the first element of a CNAME/DNAME chain anyway, hence let's settle
1048 * on always processing the RCODE as referring to the immediate look-up we do, i.e. the first element of a
1049 * CNAME/DNAME chain. This way, we uniformly handle CNAME/DNAME chains, regardless if the DNS server
1050 * incorrectly implements RCODE, whether DNSSEC is in use, or whether the DNS server only supplied us with an
1051 * incomplete CNAME/DNAME chain.
1053 * Or in other words: if we get at least one positive reply in a message we patch NXDOMAIN to become SUCCESS,
1054 * and then rely on the CNAME chasing logic to figure out that there's actually a CNAME error with a new
1057 if (t
->answer_rcode
!= DNS_RCODE_NXDOMAIN
)
1060 r
= dns_transaction_has_positive_answer(t
, NULL
);
1064 t
->answer_rcode
= DNS_RCODE_SUCCESS
;
1068 void dns_transaction_process_reply(DnsTransaction
*t
, DnsPacket
*p
, bool encrypted
) {
1069 bool retry_with_tcp
= false;
1075 assert(t
->scope
->manager
);
1077 if (t
->state
!= DNS_TRANSACTION_PENDING
)
1080 /* Increment the total failure counter only when it is the first attempt at querying and the upstream
1081 * server returns a failure response code. This ensures a more accurate count of the number of queries
1082 * that received a failure response code, as it doesn't consider retries. */
1084 if (t
->n_attempts
== 1 && !IN_SET(DNS_PACKET_RCODE(p
), DNS_RCODE_SUCCESS
, DNS_RCODE_NXDOMAIN
))
1085 t
->scope
->manager
->n_failure_responses_total
++;
1087 /* Note that this call might invalidate the query. Callers
1088 * should hence not attempt to access the query or transaction
1089 * after calling this function. */
1091 log_debug("Processing incoming packet of size %zu on transaction %" PRIu16
" (rcode=%s).",
1093 t
->id
, FORMAT_DNS_RCODE(DNS_PACKET_RCODE(p
)));
1095 switch (t
->scope
->protocol
) {
1097 case DNS_PROTOCOL_LLMNR
:
1098 /* For LLMNR we will not accept any packets from other interfaces */
1100 if (p
->ifindex
!= dns_scope_ifindex(t
->scope
))
1103 if (p
->family
!= t
->scope
->family
)
1106 /* Tentative packets are not full responses but still
1107 * useful for identifying uniqueness conflicts during
1109 if (DNS_PACKET_LLMNR_T(p
)) {
1110 dns_transaction_tentative(t
, p
);
1116 case DNS_PROTOCOL_MDNS
:
1117 /* For mDNS we will not accept any packets from other interfaces */
1119 if (p
->ifindex
!= dns_scope_ifindex(t
->scope
))
1122 if (p
->family
!= t
->scope
->family
)
1127 case DNS_PROTOCOL_DNS
:
1128 /* Note that we do not need to verify the
1129 * addresses/port numbers of incoming traffic, as we
1130 * invoked connect() on our UDP socket in which case
1131 * the kernel already does the needed verification for
1136 assert_not_reached();
1139 if (t
->received
!= p
)
1140 DNS_PACKET_REPLACE(t
->received
, dns_packet_ref(p
));
1142 t
->answer_source
= DNS_TRANSACTION_NETWORK
;
1144 if (p
->ipproto
== IPPROTO_TCP
) {
1145 if (DNS_PACKET_TC(p
)) {
1146 /* Truncated via TCP? Somebody must be fucking with us */
1147 dns_transaction_complete(t
, DNS_TRANSACTION_INVALID_REPLY
);
1151 if (DNS_PACKET_ID(p
) != t
->id
) {
1152 /* Not the reply to our query? Somebody must be fucking with us */
1153 dns_transaction_complete(t
, DNS_TRANSACTION_INVALID_REPLY
);
1158 if (DNS_PACKET_TC(p
)) {
1160 /* Truncated packets for mDNS are not allowed. Give up immediately. */
1161 if (t
->scope
->protocol
== DNS_PROTOCOL_MDNS
) {
1162 dns_transaction_complete(t
, DNS_TRANSACTION_INVALID_REPLY
);
1166 /* Response was truncated, let's try again with good old TCP */
1167 log_debug("Reply truncated, retrying via TCP.");
1168 retry_with_tcp
= true;
1170 } else if (t
->scope
->protocol
== DNS_PROTOCOL_DNS
&&
1171 DNS_PACKET_IS_FRAGMENTED(p
)) {
1173 /* Report the fragment size, so that we downgrade from LARGE to regular EDNS0 if needed */
1175 dns_server_packet_udp_fragmented(t
->server
, dns_packet_size_unfragmented(p
));
1177 if (t
->current_feature_level
> DNS_SERVER_FEATURE_LEVEL_UDP
) {
1178 /* Packet was fragmented. Let's retry with TCP to avoid fragmentation attack
1179 * issues. (We don't do that on the lowest feature level however, since crappy DNS
1180 * servers often do not implement TCP, hence falling back to TCP on fragmentation is
1181 * counter-productive there.) */
1183 log_debug("Reply fragmented, retrying via TCP. (Largest fragment size: %zu; Datagram size: %zu)",
1184 p
->fragsize
, p
->size
);
1185 retry_with_tcp
= true;
1189 if (retry_with_tcp
) {
1190 r
= dns_transaction_emit_tcp(t
);
1192 /* No servers found? Damn! */
1193 dns_transaction_complete(t
, DNS_TRANSACTION_NO_SERVERS
);
1196 if (r
== -EOPNOTSUPP
) {
1197 /* Tried to ask for DNSSEC RRs, on a server that doesn't do DNSSEC */
1198 dns_transaction_complete(t
, DNS_TRANSACTION_RR_TYPE_UNSUPPORTED
);
1202 /* On LLMNR, if we cannot connect to the host,
1203 * we immediately give up */
1204 if (t
->scope
->protocol
!= DNS_PROTOCOL_DNS
)
1207 /* On DNS, couldn't send? Try immediately again, with a new server */
1208 if (dns_transaction_limited_retry(t
))
1211 /* No new server to try, give up */
1212 dns_transaction_complete(t
, DNS_TRANSACTION_ATTEMPTS_MAX_REACHED
);
1218 /* After the superficial checks, actually parse the message. */
1219 r
= dns_packet_extract(p
);
1222 dns_server_packet_invalid(t
->server
, t
->current_feature_level
);
1224 r
= dns_transaction_maybe_restart(t
);
1227 if (r
> 0) /* Transaction got restarted... */
1231 dns_transaction_complete(t
, DNS_TRANSACTION_INVALID_REPLY
);
1235 switch (t
->scope
->protocol
) {
1237 case DNS_PROTOCOL_DNS
: {
1240 (void) dns_packet_ede_rcode(p
, &t
->answer_ede_rcode
, &t
->answer_ede_msg
);
1243 IN_SET(DNS_PACKET_RCODE(p
), DNS_RCODE_FORMERR
, DNS_RCODE_SERVFAIL
, DNS_RCODE_NOTIMP
)) {
1244 /* If the server has replied with detailed error data, using a degraded feature set
1245 * will likely not help anyone. Examine the detailed error to determine the best
1246 * course of action. */
1247 if (t
->answer_ede_rcode
>= 0 && DNS_PACKET_RCODE(p
) == DNS_RCODE_SERVFAIL
) {
1248 /* These codes are related to DNSSEC configuration errors. If accurate,
1249 * this is the domain operator's problem, and retrying won't help. */
1250 if (dns_ede_rcode_is_dnssec(t
->answer_ede_rcode
)) {
1251 log_debug("Server returned error: %s (%s%s%s). Lookup failed.",
1252 FORMAT_DNS_RCODE(DNS_PACKET_RCODE(p
)),
1253 FORMAT_DNS_EDE_RCODE(t
->answer_ede_rcode
),
1254 isempty(t
->answer_ede_msg
) ? "" : ": ",
1255 strempty(t
->answer_ede_msg
));
1257 t
->answer_dnssec_result
= DNSSEC_UPSTREAM_FAILURE
;
1258 dns_transaction_complete(t
, DNS_TRANSACTION_DNSSEC_FAILED
);
1262 /* These codes probably indicate a transient error. Let's try again. */
1263 if (IN_SET(t
->answer_ede_rcode
, DNS_EDE_RCODE_NOT_READY
, DNS_EDE_RCODE_NET_ERROR
)) {
1264 log_debug("Server returned error: %s (%s%s%s), retrying transaction.",
1265 FORMAT_DNS_RCODE(DNS_PACKET_RCODE(p
)),
1266 FORMAT_DNS_EDE_RCODE(t
->answer_ede_rcode
),
1267 isempty(t
->answer_ede_msg
) ? "" : ": ",
1268 strempty(t
->answer_ede_msg
));
1269 dns_transaction_retry(t
, false);
1273 /* OK, the query failed, but we still shouldn't degrade the feature set for
1275 log_debug("Server returned error: %s (%s%s%s)",
1276 FORMAT_DNS_RCODE(DNS_PACKET_RCODE(p
)),
1277 FORMAT_DNS_EDE_RCODE(t
->answer_ede_rcode
),
1278 isempty(t
->answer_ede_msg
) ? "" : ": ",
1279 strempty(t
->answer_ede_msg
));
1283 /* Request failed, immediately try again with reduced features */
1285 if (t
->current_feature_level
<= DNS_SERVER_FEATURE_LEVEL_UDP
) {
1287 /* This was already at UDP feature level? If so, it doesn't make sense to downgrade
1288 * this transaction anymore, but let's see if it might make sense to send the request
1289 * to a different DNS server instead. If not let's process the response, and accept the
1290 * rcode. Note that we don't retry on TCP, since that's a suitable way to mitigate
1291 * packet loss, but is not going to give us better rcodes should we actually have
1292 * managed to get them already at UDP level. */
1294 if (dns_transaction_limited_retry(t
))
1297 /* Give up, accept the rcode */
1298 log_debug("Server returned error: %s", FORMAT_DNS_RCODE(DNS_PACKET_RCODE(p
)));
1302 /* SERVFAIL can happen for many reasons and may be transient.
1303 * To avoid unnecessary downgrades retry once with the initial level.
1304 * Check for clamp_feature_level_servfail having an invalid value as a sign that this is the
1305 * first attempt to downgrade. If so, clamp to the current value so that the transaction
1306 * is retried without actually downgrading. If the next try also fails we will downgrade by
1307 * hitting the else branch below. */
1308 if (DNS_PACKET_RCODE(p
) == DNS_RCODE_SERVFAIL
&&
1309 t
->clamp_feature_level_servfail
< 0) {
1310 t
->clamp_feature_level_servfail
= t
->current_feature_level
;
1311 log_debug("Server returned error %s, retrying transaction.",
1312 FORMAT_DNS_RCODE(DNS_PACKET_RCODE(p
)));
1314 /* Reduce this feature level by one and try again. */
1315 switch (t
->current_feature_level
) {
1316 case DNS_SERVER_FEATURE_LEVEL_TLS_DO
:
1317 t
->clamp_feature_level_servfail
= DNS_SERVER_FEATURE_LEVEL_TLS_PLAIN
;
1319 case DNS_SERVER_FEATURE_LEVEL_TLS_PLAIN
+ 1:
1320 /* Skip plain TLS when TLS is not supported */
1321 t
->clamp_feature_level_servfail
= DNS_SERVER_FEATURE_LEVEL_TLS_PLAIN
- 1;
1324 t
->clamp_feature_level_servfail
= t
->current_feature_level
- 1;
1327 log_debug("Server returned error %s, retrying transaction with reduced feature level %s.",
1328 FORMAT_DNS_RCODE(DNS_PACKET_RCODE(p
)),
1329 dns_server_feature_level_to_string(t
->clamp_feature_level_servfail
));
1332 dns_transaction_retry(t
, false /* use the same server */);
1336 if (DNS_PACKET_RCODE(p
) == DNS_RCODE_REFUSED
) {
1337 /* This server refused our request? If so, try again, use a different server */
1338 if (t
->answer_ede_rcode
>= 0)
1339 log_debug("Server returned REFUSED (%s), switching servers, and retrying.",
1340 FORMAT_DNS_EDE_RCODE(t
->answer_ede_rcode
));
1342 log_debug("Server returned REFUSED, switching servers, and retrying.");
1344 if (dns_transaction_limited_retry(t
))
1350 if (DNS_PACKET_TC(p
))
1351 dns_server_packet_truncated(t
->server
, t
->current_feature_level
);
1356 case DNS_PROTOCOL_LLMNR
:
1357 case DNS_PROTOCOL_MDNS
:
1358 dns_scope_packet_received(t
->scope
, p
->timestamp
- t
->start_usec
);
1362 assert_not_reached();
1366 /* Report that we successfully received a valid packet with a good rcode after we initially got a bad
1367 * rcode and subsequently downgraded the protocol */
1369 if (IN_SET(DNS_PACKET_RCODE(p
), DNS_RCODE_SUCCESS
, DNS_RCODE_NXDOMAIN
) &&
1370 t
->clamp_feature_level_servfail
!= _DNS_SERVER_FEATURE_LEVEL_INVALID
)
1371 dns_server_packet_rcode_downgrade(t
->server
, t
->clamp_feature_level_servfail
);
1373 /* Report that the OPT RR was missing */
1375 dns_server_packet_bad_opt(t
->server
, t
->current_feature_level
);
1377 /* Report that the server didn't copy our query DO bit from request to response */
1378 if (DNS_PACKET_DO(t
->sent
) && !DNS_PACKET_DO(t
->received
))
1379 dns_server_packet_do_off(t
->server
, t
->current_feature_level
);
1381 /* Report that we successfully received a packet. We keep track of the largest packet
1382 * size/fragment size we got. Which is useful for announcing the EDNS(0) packet size we can
1383 * receive to our server. */
1384 dns_server_packet_received(t
->server
, p
->ipproto
, t
->current_feature_level
, dns_packet_size_unfragmented(p
));
1387 /* See if we know things we didn't know before that indicate we better restart the lookup immediately. */
1388 r
= dns_transaction_maybe_restart(t
);
1391 if (r
> 0) /* Transaction got restarted... */
1394 /* When dealing with protocols other than mDNS only consider responses with equivalent query section
1395 * to the request. For mDNS this check doesn't make sense, because the section 6 of RFC6762 states
1396 * that "Multicast DNS responses MUST NOT contain any questions in the Question Section". */
1397 if (t
->scope
->protocol
!= DNS_PROTOCOL_MDNS
) {
1398 r
= dns_packet_is_reply_for(p
, dns_transaction_key(t
));
1402 dns_transaction_complete(t
, DNS_TRANSACTION_INVALID_REPLY
);
1407 /* Install the answer as answer to the transaction. We ref the answer twice here: the main `answer`
1408 * field is later replaced by the DNSSEC validated subset. The 'answer_auxiliary' field carries the
1409 * original complete record set, including RRSIG and friends. We use this when passing data to
1410 * clients that ask for DNSSEC metadata. */
1411 DNS_ANSWER_REPLACE(t
->answer
, dns_answer_ref(p
->answer
));
1412 t
->answer_rcode
= DNS_PACKET_RCODE(p
);
1413 t
->answer_dnssec_result
= _DNSSEC_RESULT_INVALID
;
1414 SET_FLAG(t
->answer_query_flags
, SD_RESOLVED_AUTHENTICATED
, false);
1415 SET_FLAG(t
->answer_query_flags
, SD_RESOLVED_CONFIDENTIAL
, encrypted
);
1417 r
= dns_transaction_fix_rcode(t
);
1421 /* Block GC while starting requests for additional DNSSEC RRs */
1423 r
= dns_transaction_request_dnssec_keys(t
);
1426 /* Maybe the transaction is ready for GC'ing now? If so, free it and return. */
1427 if (!dns_transaction_gc(t
))
1430 /* Requesting additional keys might have resulted in this transaction to fail, since the auxiliary
1431 * request failed for some reason. If so, we are not in pending state anymore, and we should exit
1433 if (t
->state
!= DNS_TRANSACTION_PENDING
)
1438 /* There are DNSSEC transactions pending now. Update the state accordingly. */
1439 t
->state
= DNS_TRANSACTION_VALIDATING
;
1440 dns_transaction_close_connection(t
, true);
1441 dns_transaction_stop_timeout(t
);
1445 dns_transaction_process_dnssec(t
);
1449 dns_transaction_complete_errno(t
, r
);
1452 static int on_dns_packet(sd_event_source
*s
, int fd
, uint32_t revents
, void *userdata
) {
1453 _cleanup_(dns_packet_unrefp
) DnsPacket
*p
= NULL
;
1454 DnsTransaction
*t
= ASSERT_PTR(userdata
);
1459 r
= manager_recv(t
->scope
->manager
, fd
, DNS_PROTOCOL_DNS
, &p
);
1461 if (ERRNO_IS_DISCONNECT(r
)) {
1464 /* UDP connection failures get reported via ICMP and then are possibly delivered to us on the
1465 * next recvmsg(). Treat this like a lost packet. */
1467 log_debug_errno(r
, "Connection failure for DNS UDP packet: %m");
1468 assert_se(sd_event_now(t
->scope
->manager
->event
, CLOCK_BOOTTIME
, &usec
) >= 0);
1469 dns_server_packet_lost(t
->server
, IPPROTO_UDP
, t
->current_feature_level
);
1471 dns_transaction_close_connection(t
, /* use_graveyard = */ false);
1473 if (dns_transaction_limited_retry(t
)) /* Try a different server */
1476 dns_transaction_complete_errno(t
, r
);
1480 /* Spurious wakeup without any data */
1483 r
= dns_packet_validate_reply(p
);
1485 log_debug_errno(r
, "Received invalid DNS packet as response, ignoring: %m");
1489 log_debug("Received inappropriate DNS packet as response, ignoring.");
1493 if (DNS_PACKET_ID(p
) != t
->id
) {
1494 log_debug("Received packet with incorrect transaction ID, ignoring.");
1498 dns_transaction_process_reply(t
, p
, false);
1502 static int dns_transaction_emit_udp(DnsTransaction
*t
) {
1507 if (t
->scope
->protocol
== DNS_PROTOCOL_DNS
) {
1509 r
= dns_transaction_pick_server(t
);
1513 if (manager_server_is_stub(t
->scope
->manager
, t
->server
))
1516 if (t
->current_feature_level
< DNS_SERVER_FEATURE_LEVEL_UDP
|| DNS_SERVER_FEATURE_LEVEL_IS_TLS(t
->current_feature_level
))
1517 return -EAGAIN
; /* Sorry, can't do UDP, try TCP! */
1519 if (!t
->bypass
&& !dns_server_dnssec_supported(t
->server
) && dns_type_is_dnssec(dns_transaction_key(t
)->type
))
1522 if (r
> 0 || t
->dns_udp_fd
< 0) { /* Server changed, or no connection yet. */
1525 dns_transaction_close_connection(t
, true);
1527 /* Before we allocate a new UDP socket, let's process the graveyard a bit to free some fds */
1528 manager_socket_graveyard_process(t
->scope
->manager
);
1530 fd
= dns_scope_socket_udp(t
->scope
, t
->server
);
1534 r
= sd_event_add_io(t
->scope
->manager
->event
, &t
->dns_udp_event_source
, fd
, EPOLLIN
, on_dns_packet
, t
);
1540 (void) sd_event_source_set_description(t
->dns_udp_event_source
, "dns-transaction-udp");
1545 r
= dns_server_adjust_opt(t
->server
, t
->sent
, t
->current_feature_level
);
1550 dns_transaction_close_connection(t
, true);
1552 r
= dns_scope_emit_udp(t
->scope
, t
->dns_udp_fd
, t
->server
? t
->server
->family
: AF_UNSPEC
, t
->sent
);
1556 dns_transaction_reset_answer(t
);
1561 static int on_transaction_timeout(sd_event_source
*s
, usec_t usec
, void *userdata
) {
1562 DnsTransaction
*t
= ASSERT_PTR(userdata
);
1566 t
->seen_timeout
= true;
1568 if (t
->initial_jitter_scheduled
&& !t
->initial_jitter_elapsed
) {
1569 log_debug("Initial jitter phase for transaction %" PRIu16
" elapsed.", t
->id
);
1570 t
->initial_jitter_elapsed
= true;
1572 /* Timeout reached? Increase the timeout for the server used */
1573 switch (t
->scope
->protocol
) {
1575 case DNS_PROTOCOL_DNS
:
1577 dns_server_packet_lost(t
->server
, t
->stream
? IPPROTO_TCP
: IPPROTO_UDP
, t
->current_feature_level
);
1580 case DNS_PROTOCOL_LLMNR
:
1581 case DNS_PROTOCOL_MDNS
:
1582 dns_scope_packet_lost(t
->scope
, usec
- t
->start_usec
);
1586 assert_not_reached();
1589 log_debug("Timeout reached on transaction %" PRIu16
".", t
->id
);
1592 dns_transaction_retry(t
, /* next_server= */ true); /* try a different server, but given this means
1593 * packet loss, let's do so even if we already
1598 static int dns_transaction_setup_timeout(
1600 usec_t timeout_usec
/* relative */,
1601 usec_t next_usec
/* CLOCK_BOOTTIME */) {
1607 dns_transaction_stop_timeout(t
);
1609 r
= sd_event_add_time_relative(
1610 t
->scope
->manager
->event
,
1611 &t
->timeout_event_source
,
1614 on_transaction_timeout
, t
);
1618 (void) sd_event_source_set_description(t
->timeout_event_source
, "dns-transaction-timeout");
1620 t
->next_attempt_after
= next_usec
;
1621 t
->state
= DNS_TRANSACTION_PENDING
;
1625 static usec_t
transaction_get_resend_timeout(DnsTransaction
*t
) {
1629 switch (t
->scope
->protocol
) {
1631 case DNS_PROTOCOL_DNS
:
1633 /* When we do TCP, grant a much longer timeout, as in this case there's no need for us to quickly
1634 * resend, as the kernel does that anyway for us, and we really don't want to interrupt it in that
1637 return TRANSACTION_TCP_TIMEOUT_USEC
;
1639 return DNS_TIMEOUT_USEC
;
1641 case DNS_PROTOCOL_MDNS
:
1643 return MDNS_PROBING_INTERVAL_USEC
;
1645 /* See RFC 6762 Section 5.1 suggests that timeout should be a few seconds. */
1646 assert(t
->n_attempts
> 0);
1647 return (1 << (t
->n_attempts
- 1)) * USEC_PER_SEC
;
1649 case DNS_PROTOCOL_LLMNR
:
1650 return t
->scope
->resend_timeout
;
1653 assert_not_reached();
1657 static void dns_transaction_randomize_answer(DnsTransaction
*t
) {
1662 /* Randomizes the order of the answer array. This is done for all cached responses, so that we return
1663 * a different order each time. We do this only for DNS traffic, in order to do some minimal, crappy
1664 * load balancing. We don't do this for LLMNR or mDNS, since the order (preferring link-local
1665 * addresses, and such like) might have meaning there, and load balancing is pointless. */
1667 if (t
->scope
->protocol
!= DNS_PROTOCOL_DNS
)
1670 /* No point in randomizing, if there's just one RR */
1671 if (dns_answer_size(t
->answer
) <= 1)
1674 r
= dns_answer_reserve_or_clone(&t
->answer
, 0);
1675 if (r
< 0) /* If this fails, just don't randomize, this is non-essential stuff after all */
1676 return (void) log_debug_errno(r
, "Failed to clone answer record, not randomizing RR order of answer: %m");
1678 dns_answer_randomize(t
->answer
);
1681 static int dns_transaction_prepare(DnsTransaction
*t
, usec_t ts
) {
1686 /* Returns 0 if dns_transaction_complete() has been called. In that case the transaction and query
1687 * candidate objects may have been invalidated and must not be accessed. Returns 1 if the transaction
1688 * has been prepared. */
1690 dns_transaction_stop_timeout(t
);
1692 if (t
->n_attempts
== 1 && t
->seen_timeout
)
1693 t
->scope
->manager
->n_timeouts_total
++;
1695 if (!dns_scope_network_good(t
->scope
)) {
1696 dns_transaction_complete(t
, DNS_TRANSACTION_NETWORK_DOWN
);
1700 if (t
->n_attempts
>= TRANSACTION_ATTEMPTS_MAX(t
->scope
->protocol
)) {
1701 DnsTransactionState result
;
1703 if (t
->scope
->protocol
== DNS_PROTOCOL_LLMNR
)
1704 /* If we didn't find anything on LLMNR, it's not an error, but a failure to resolve
1706 result
= DNS_TRANSACTION_NOT_FOUND
;
1708 result
= DNS_TRANSACTION_ATTEMPTS_MAX_REACHED
;
1710 dns_transaction_complete(t
, result
);
1714 if (t
->scope
->protocol
== DNS_PROTOCOL_LLMNR
&& t
->tried_stream
) {
1715 /* If we already tried via a stream, then we don't
1716 * retry on LLMNR. See RFC 4795, Section 2.7. */
1717 dns_transaction_complete(t
, DNS_TRANSACTION_ATTEMPTS_MAX_REACHED
);
1724 dns_transaction_reset_answer(t
);
1725 dns_transaction_flush_dnssec_transactions(t
);
1727 /* Check the trust anchor. Do so only on classic DNS, since DNSSEC does not apply otherwise. */
1728 if (t
->scope
->protocol
== DNS_PROTOCOL_DNS
&&
1729 !FLAGS_SET(t
->query_flags
, SD_RESOLVED_NO_TRUST_ANCHOR
)) {
1730 r
= dns_trust_anchor_lookup_positive(&t
->scope
->manager
->trust_anchor
, dns_transaction_key(t
), &t
->answer
);
1734 t
->answer_rcode
= DNS_RCODE_SUCCESS
;
1735 t
->answer_source
= DNS_TRANSACTION_TRUST_ANCHOR
;
1736 SET_FLAG(t
->answer_query_flags
, SD_RESOLVED_AUTHENTICATED
|SD_RESOLVED_CONFIDENTIAL
, true);
1737 dns_transaction_complete(t
, DNS_TRANSACTION_SUCCESS
);
1741 if (dns_name_is_root(dns_resource_key_name(dns_transaction_key(t
))) &&
1742 dns_transaction_key(t
)->type
== DNS_TYPE_DS
) {
1744 /* Hmm, this is a request for the root DS? A DS RR doesn't exist in the root zone,
1745 * and if our trust anchor didn't know it either, this means we cannot do any DNSSEC
1748 if (t
->scope
->dnssec_mode
== DNSSEC_ALLOW_DOWNGRADE
) {
1749 /* We are in downgrade mode. In this case, synthesize an unsigned empty
1750 * response, so that the any lookup depending on this one can continue
1751 * assuming there was no DS, and hence the root zone was unsigned. */
1753 t
->answer_rcode
= DNS_RCODE_SUCCESS
;
1754 t
->answer_source
= DNS_TRANSACTION_TRUST_ANCHOR
;
1755 SET_FLAG(t
->answer_query_flags
, SD_RESOLVED_AUTHENTICATED
, false);
1756 SET_FLAG(t
->answer_query_flags
, SD_RESOLVED_CONFIDENTIAL
, true);
1757 dns_transaction_complete(t
, DNS_TRANSACTION_SUCCESS
);
1759 /* If we are not in downgrade mode, then fail the lookup, because we cannot
1760 * reasonably answer it. There might be DS RRs, but we don't know them, and
1761 * the DNS server won't tell them to us (and even if it would, we couldn't
1762 * validate and trust them. */
1763 dns_transaction_complete(t
, DNS_TRANSACTION_NO_TRUST_ANCHOR
);
1769 /* Check the zone. */
1770 if (!FLAGS_SET(t
->query_flags
, SD_RESOLVED_NO_ZONE
)) {
1771 r
= dns_zone_lookup(&t
->scope
->zone
, dns_transaction_key(t
), dns_scope_ifindex(t
->scope
), &t
->answer
, NULL
, NULL
);
1775 t
->answer_rcode
= DNS_RCODE_SUCCESS
;
1776 t
->answer_source
= DNS_TRANSACTION_ZONE
;
1777 SET_FLAG(t
->answer_query_flags
, SD_RESOLVED_AUTHENTICATED
|SD_RESOLVED_CONFIDENTIAL
, true);
1778 dns_transaction_complete(t
, DNS_TRANSACTION_SUCCESS
);
1783 /* Check the cache. */
1784 if (!FLAGS_SET(t
->query_flags
, SD_RESOLVED_NO_CACHE
)) {
1786 /* Before trying the cache, let's make sure we figured out a server to use. Should this cause
1787 * a change of server this might flush the cache. */
1788 (void) dns_scope_get_dns_server(t
->scope
);
1790 /* Let's then prune all outdated entries */
1791 dns_cache_prune(&t
->scope
->cache
);
1793 /* For the initial attempt or when no stale data is requested, disable serve stale
1794 * and answer the question from the cache (honors ttl property).
1795 * On the second attempt, if StaleRetentionSec is greater than zero,
1796 * try to answer the question using stale date (honors until property) */
1797 uint64_t query_flags
= t
->query_flags
;
1798 if (t
->n_attempts
== 1 || t
->scope
->manager
->stale_retention_usec
== 0)
1799 query_flags
|= SD_RESOLVED_NO_STALE
;
1801 r
= dns_cache_lookup(
1803 dns_transaction_key(t
),
1808 &t
->answer_query_flags
,
1809 &t
->answer_dnssec_result
);
1813 dns_transaction_randomize_answer(t
);
1815 if (t
->bypass
&& t
->scope
->protocol
== DNS_PROTOCOL_DNS
&& !t
->received
)
1816 /* When bypass mode is on, do not use cached data unless it came with a full
1818 dns_transaction_reset_answer(t
);
1820 if (t
->n_attempts
> 1 && !FLAGS_SET(query_flags
, SD_RESOLVED_NO_STALE
)) {
1822 if (t
->answer_rcode
== DNS_RCODE_SUCCESS
) {
1823 if (t
->seen_timeout
)
1824 t
->scope
->manager
->n_timeouts_served_stale_total
++;
1826 t
->scope
->manager
->n_failure_responses_served_stale_total
++;
1829 char key_str
[DNS_RESOURCE_KEY_STRING_MAX
];
1830 log_debug("Serve Stale response rcode=%s for %s",
1831 FORMAT_DNS_RCODE(t
->answer_rcode
),
1832 dns_resource_key_to_string(dns_transaction_key(t
), key_str
, sizeof key_str
));
1835 t
->answer_source
= DNS_TRANSACTION_CACHE
;
1836 if (t
->answer_rcode
== DNS_RCODE_SUCCESS
)
1837 dns_transaction_complete(t
, DNS_TRANSACTION_SUCCESS
);
1840 (void) dns_packet_ede_rcode(t
->received
, &t
->answer_ede_rcode
, &t
->answer_ede_msg
);
1842 dns_transaction_complete(t
, DNS_TRANSACTION_RCODE_FAILURE
);
1849 if (FLAGS_SET(t
->query_flags
, SD_RESOLVED_NO_NETWORK
)) {
1850 dns_transaction_complete(t
, DNS_TRANSACTION_NO_SOURCE
);
1857 static int dns_packet_append_zone(DnsPacket
*p
, DnsTransaction
*t
, DnsResourceKey
*k
, unsigned *nscount
) {
1858 _cleanup_(dns_answer_unrefp
) DnsAnswer
*answer
= NULL
;
1866 if (k
->type
!= DNS_TYPE_ANY
)
1869 r
= dns_zone_lookup(&t
->scope
->zone
, k
, t
->scope
->link
->ifindex
, &answer
, NULL
, &tentative
);
1873 return dns_packet_append_answer(p
, answer
, nscount
);
1876 static int mdns_make_dummy_packet(DnsTransaction
*t
, DnsPacket
**ret_packet
, Set
**ret_keys
) {
1877 _cleanup_(dns_packet_unrefp
) DnsPacket
*p
= NULL
;
1878 _cleanup_set_free_ Set
*keys
= NULL
;
1879 bool add_known_answers
= false;
1886 assert(t
->scope
->protocol
== DNS_PROTOCOL_MDNS
);
1890 r
= dns_packet_new_query(&p
, t
->scope
->protocol
, 0, false);
1894 r
= dns_packet_append_key(p
, dns_transaction_key(t
), 0, NULL
);
1900 if (dns_key_is_shared(dns_transaction_key(t
)))
1901 add_known_answers
= true;
1903 r
= dns_packet_append_zone(p
, t
, dns_transaction_key(t
), NULL
);
1907 /* Save appended keys */
1908 r
= set_ensure_put(&keys
, &dns_resource_key_hash_ops
, dns_transaction_key(t
));
1912 assert_se(sd_event_now(t
->scope
->manager
->event
, CLOCK_BOOTTIME
, &ts
) >= 0);
1914 LIST_FOREACH(transactions_by_scope
, other
, t
->scope
->transactions
) {
1916 /* Skip ourselves */
1920 if (other
->state
!= DNS_TRANSACTION_PENDING
)
1923 if (other
->next_attempt_after
> ts
)
1926 if (!set_contains(keys
, dns_transaction_key(other
))) {
1927 size_t saved_packet_size
;
1929 r
= dns_packet_append_key(p
, dns_transaction_key(other
), 0, &saved_packet_size
);
1930 /* If we can't stuff more questions into the packet, just give up.
1931 * One of the 'other' transactions will fire later and take care of the rest. */
1937 r
= dns_packet_append_zone(p
, t
, dns_transaction_key(other
), NULL
);
1938 if (r
== -EMSGSIZE
) {
1939 dns_packet_truncate(p
, saved_packet_size
);
1945 r
= set_ensure_put(&keys
, &dns_resource_key_hash_ops
, dns_transaction_key(other
));
1950 r
= dns_transaction_prepare(other
, ts
);
1954 /* In this case, not only this transaction, but multiple transactions may be
1955 * freed. Hence, we need to restart the loop. */
1958 usec_t timeout
= transaction_get_resend_timeout(other
);
1959 r
= dns_transaction_setup_timeout(other
, timeout
, usec_add(ts
, timeout
));
1963 if (dns_key_is_shared(dns_transaction_key(other
)))
1964 add_known_answers
= true;
1967 if (qdcount
>= UINT16_MAX
)
1971 DNS_PACKET_HEADER(p
)->qdcount
= htobe16(qdcount
);
1973 /* Append known answers section if we're asking for any shared record */
1974 if (add_known_answers
) {
1975 r
= dns_cache_export_shared_to_packet(&t
->scope
->cache
, p
, ts
, 0);
1980 *ret_packet
= TAKE_PTR(p
);
1981 *ret_keys
= TAKE_PTR(keys
);
1982 return add_known_answers
;
1985 static int dns_transaction_make_packet_mdns(DnsTransaction
*t
) {
1986 _cleanup_(dns_packet_unrefp
) DnsPacket
*p
= NULL
, *dummy
= NULL
;
1987 _cleanup_set_free_ Set
*keys
= NULL
;
1988 bool add_known_answers
;
1994 assert(t
->scope
->protocol
== DNS_PROTOCOL_MDNS
);
1996 /* Discard any previously prepared packet, so we can start over and coalesce again */
1997 t
->sent
= dns_packet_unref(t
->sent
);
1999 /* First, create a dummy packet to calculate the number of known answers to be appended in the first packet. */
2001 r
= mdns_make_dummy_packet(t
, &dummy
, &keys
);
2007 add_known_answers
= r
;
2011 /* Then, create actual packet. */
2012 r
= dns_packet_new_query(&p
, t
->scope
->protocol
, 0, false);
2018 SET_FOREACH(k
, keys
) {
2019 r
= dns_packet_append_key(p
, k
, 0, NULL
);
2024 DNS_PACKET_HEADER(p
)->qdcount
= htobe16(c
);
2027 if (add_known_answers
) {
2030 assert_se(sd_event_now(t
->scope
->manager
->event
, CLOCK_BOOTTIME
, &ts
) >= 0);
2032 r
= dns_cache_export_shared_to_packet(&t
->scope
->cache
, p
, ts
, be16toh(DNS_PACKET_HEADER(dummy
)->ancount
));
2039 SET_FOREACH(k
, keys
) {
2040 r
= dns_packet_append_zone(p
, t
, k
, &c
);
2044 DNS_PACKET_HEADER(p
)->nscount
= htobe16(c
);
2046 t
->sent
= TAKE_PTR(p
);
2050 static int dns_transaction_make_packet(DnsTransaction
*t
) {
2051 _cleanup_(dns_packet_unrefp
) DnsPacket
*p
= NULL
;
2056 if (t
->scope
->protocol
== DNS_PROTOCOL_MDNS
)
2057 return dns_transaction_make_packet_mdns(t
);
2062 if (t
->bypass
&& t
->bypass
->protocol
== t
->scope
->protocol
) {
2063 /* If bypass logic is enabled and the protocol if the original packet and our scope match,
2064 * take the original packet, copy it, and patch in our new ID */
2065 r
= dns_packet_dup(&p
, t
->bypass
);
2069 r
= dns_packet_new_query(
2070 &p
, t
->scope
->protocol
,
2071 /* min_alloc_dsize = */ 0,
2072 /* dnssec_cd = */ !FLAGS_SET(t
->query_flags
, SD_RESOLVED_NO_VALIDATE
) &&
2073 t
->scope
->dnssec_mode
!= DNSSEC_NO
);
2077 r
= dns_packet_append_key(p
, dns_transaction_key(t
), 0, NULL
);
2081 DNS_PACKET_HEADER(p
)->qdcount
= htobe16(1);
2084 DNS_PACKET_HEADER(p
)->id
= t
->id
;
2086 t
->sent
= TAKE_PTR(p
);
2090 int dns_transaction_go(DnsTransaction
*t
) {
2093 char key_str
[DNS_RESOURCE_KEY_STRING_MAX
];
2097 /* Returns > 0 if the transaction is now pending, returns 0 if could be processed immediately and has
2098 * finished now. In the latter case, the transaction and query candidate objects must not be accessed.
2101 assert_se(sd_event_now(t
->scope
->manager
->event
, CLOCK_BOOTTIME
, &ts
) >= 0);
2103 r
= dns_transaction_prepare(t
, ts
);
2107 log_debug("Firing %s transaction %" PRIu16
" for <%s> scope %s on %s/%s (validate=%s).",
2108 t
->bypass
? "bypass" : "regular",
2110 dns_resource_key_to_string(dns_transaction_key(t
), key_str
, sizeof key_str
),
2111 dns_protocol_to_string(t
->scope
->protocol
),
2112 t
->scope
->link
? t
->scope
->link
->ifname
: "*",
2113 af_to_name_short(t
->scope
->family
),
2114 yes_no(!FLAGS_SET(t
->query_flags
, SD_RESOLVED_NO_VALIDATE
)));
2116 if (!t
->initial_jitter_scheduled
&&
2117 IN_SET(t
->scope
->protocol
, DNS_PROTOCOL_LLMNR
, DNS_PROTOCOL_MDNS
)) {
2120 /* RFC 4795 Section 2.7 suggests all LLMNR queries should be delayed by a random time from 0 to
2122 * RFC 6762 Section 8.1 suggests initial probe queries should be delayed by a random time from
2125 t
->initial_jitter_scheduled
= true;
2128 switch (t
->scope
->protocol
) {
2130 case DNS_PROTOCOL_LLMNR
:
2131 jitter
= random_u64_range(LLMNR_JITTER_INTERVAL_USEC
);
2134 case DNS_PROTOCOL_MDNS
:
2136 jitter
= random_u64_range(MDNS_PROBING_INTERVAL_USEC
);
2141 assert_not_reached();
2144 r
= dns_transaction_setup_timeout(t
, jitter
, ts
);
2148 log_debug("Delaying %s transaction %" PRIu16
" for " USEC_FMT
"us.",
2149 dns_protocol_to_string(t
->scope
->protocol
),
2155 /* Otherwise, we need to ask the network */
2156 r
= dns_transaction_make_packet(t
);
2160 if (t
->scope
->protocol
== DNS_PROTOCOL_LLMNR
&&
2161 (dns_name_endswith(dns_resource_key_name(dns_transaction_key(t
)), "in-addr.arpa") > 0 ||
2162 dns_name_endswith(dns_resource_key_name(dns_transaction_key(t
)), "ip6.arpa") > 0)) {
2164 /* RFC 4795, Section 2.4. says reverse lookups shall
2165 * always be made via TCP on LLMNR */
2166 r
= dns_transaction_emit_tcp(t
);
2168 /* Try via UDP, and if that fails due to large size or lack of
2169 * support try via TCP */
2170 r
= dns_transaction_emit_udp(t
);
2172 log_debug("Sending query via TCP since it is too large.");
2173 else if (r
== -EAGAIN
)
2174 log_debug("Sending query via TCP since UDP isn't supported or DNS-over-TLS is selected.");
2175 else if (r
== -EPERM
)
2176 log_debug("Sending query via TCP since UDP is blocked.");
2177 if (IN_SET(r
, -EMSGSIZE
, -EAGAIN
, -EPERM
))
2178 r
= dns_transaction_emit_tcp(t
);
2181 if (t
->scope
->protocol
!= DNS_PROTOCOL_DNS
)
2184 /* One of our own stub listeners */
2185 log_debug_errno(r
, "Detected that specified DNS server is our own extra listener, switching DNS servers.");
2187 dns_scope_next_dns_server(t
->scope
, t
->server
);
2189 if (dns_scope_get_dns_server(t
->scope
) == t
->server
) {
2190 log_debug_errno(r
, "Still pointing to extra listener after switching DNS servers, refusing operation.");
2191 dns_transaction_complete(t
, DNS_TRANSACTION_STUB_LOOP
);
2195 return dns_transaction_go(t
);
2198 /* No servers to send this to? */
2199 dns_transaction_complete(t
, DNS_TRANSACTION_NO_SERVERS
);
2202 if (r
== -EOPNOTSUPP
) {
2203 /* Tried to ask for DNSSEC RRs, on a server that doesn't do DNSSEC */
2204 dns_transaction_complete(t
, DNS_TRANSACTION_RR_TYPE_UNSUPPORTED
);
2207 if (t
->scope
->protocol
== DNS_PROTOCOL_LLMNR
&& ERRNO_IS_NEG_DISCONNECT(r
)) {
2208 /* On LLMNR, if we cannot connect to a host via TCP when doing reverse lookups. This means we cannot
2209 * answer this request with this protocol. */
2210 dns_transaction_complete(t
, DNS_TRANSACTION_NOT_FOUND
);
2214 if (t
->scope
->protocol
!= DNS_PROTOCOL_DNS
)
2217 /* Couldn't send? Try immediately again, with a new server */
2218 dns_scope_next_dns_server(t
->scope
, t
->server
);
2220 return dns_transaction_go(t
);
2223 usec_t timeout
= transaction_get_resend_timeout(t
);
2224 r
= dns_transaction_setup_timeout(t
, timeout
, usec_add(ts
, timeout
));
2231 static int dns_transaction_find_cyclic(DnsTransaction
*t
, DnsTransaction
*aux
) {
2238 /* Try to find cyclic dependencies between transaction objects */
2243 SET_FOREACH(n
, aux
->dnssec_transactions
) {
2244 r
= dns_transaction_find_cyclic(t
, n
);
2252 static int dns_transaction_add_dnssec_transaction(DnsTransaction
*t
, DnsResourceKey
*key
, DnsTransaction
**ret
) {
2253 _cleanup_(dns_transaction_gcp
) DnsTransaction
*aux
= NULL
;
2260 aux
= dns_scope_find_transaction(t
->scope
, key
, t
->query_flags
);
2262 r
= dns_transaction_new(&aux
, t
->scope
, key
, NULL
, t
->query_flags
);
2266 if (set_contains(t
->dnssec_transactions
, aux
)) {
2271 r
= dns_transaction_find_cyclic(t
, aux
);
2275 char s
[DNS_RESOURCE_KEY_STRING_MAX
], saux
[DNS_RESOURCE_KEY_STRING_MAX
];
2277 return log_debug_errno(SYNTHETIC_ERRNO(ELOOP
),
2278 "Potential cyclic dependency, refusing to add transaction %" PRIu16
" (%s) as dependency for %" PRIu16
" (%s).",
2280 dns_resource_key_to_string(dns_transaction_key(t
), s
, sizeof s
),
2282 dns_resource_key_to_string(dns_transaction_key(aux
), saux
, sizeof saux
));
2286 r
= set_ensure_allocated(&aux
->notify_transactions_done
, NULL
);
2290 r
= set_ensure_put(&t
->dnssec_transactions
, NULL
, aux
);
2294 r
= set_ensure_put(&aux
->notify_transactions
, NULL
, t
);
2296 (void) set_remove(t
->dnssec_transactions
, aux
);
2300 *ret
= TAKE_PTR(aux
);
2304 static int dns_transaction_request_dnssec_rr(DnsTransaction
*t
, DnsResourceKey
*key
) {
2305 _cleanup_(dns_answer_unrefp
) DnsAnswer
*a
= NULL
;
2306 DnsTransaction
*aux
;
2312 /* Try to get the data from the trust anchor */
2313 r
= dns_trust_anchor_lookup_positive(&t
->scope
->manager
->trust_anchor
, key
, &a
);
2317 r
= dns_answer_extend(&t
->validated_keys
, a
);
2324 /* This didn't work, ask for it via the network/cache then. */
2325 r
= dns_transaction_add_dnssec_transaction(t
, key
, &aux
);
2326 if (r
== -ELOOP
) /* This would result in a cyclic dependency */
2331 if (aux
->state
== DNS_TRANSACTION_NULL
) {
2332 r
= dns_transaction_go(aux
);
2340 static int dns_transaction_negative_trust_anchor_lookup(DnsTransaction
*t
, const char *name
) {
2345 /* Check whether the specified name is in the NTA
2346 * database, either in the global one, or the link-local
2349 r
= dns_trust_anchor_lookup_negative(&t
->scope
->manager
->trust_anchor
, name
);
2353 if (!t
->scope
->link
)
2356 return link_negative_trust_anchor_lookup(t
->scope
->link
, name
);
2359 static int dns_transaction_has_negative_answer(DnsTransaction
*t
) {
2364 /* Checks whether the answer is negative, and lacks NSEC/NSEC3
2365 * RRs to prove it */
2367 r
= dns_transaction_has_positive_answer(t
, NULL
);
2373 /* Is this key explicitly listed as a negative trust anchor?
2374 * If so, it's nothing we need to care about */
2375 r
= dns_transaction_negative_trust_anchor_lookup(t
, dns_resource_key_name(dns_transaction_key(t
)));
2381 static int dns_transaction_is_primary_response(DnsTransaction
*t
, DnsResourceRecord
*rr
) {
2387 /* Check if the specified RR is the "primary" response,
2388 * i.e. either matches the question precisely or is a
2389 * CNAME/DNAME for it. */
2391 r
= dns_resource_key_match_rr(dns_transaction_key(t
), rr
, NULL
);
2395 return dns_resource_key_match_cname_or_dname(dns_transaction_key(t
), rr
->key
, NULL
);
2398 static bool dns_transaction_dnssec_supported(DnsTransaction
*t
) {
2401 /* Checks whether our transaction's DNS server is assumed to be compatible with DNSSEC. Returns false as soon
2402 * as we changed our mind about a server, and now believe it is incompatible with DNSSEC. */
2404 if (t
->scope
->protocol
!= DNS_PROTOCOL_DNS
)
2407 /* If we have picked no server, then we are working from the cache or some other source, and DNSSEC might well
2408 * be supported, hence return true. */
2412 /* Note that we do not check the feature level actually used for the transaction but instead the feature level
2413 * the server is known to support currently, as the transaction feature level might be lower than what the
2414 * server actually supports, since we might have downgraded this transaction's feature level because we got a
2415 * SERVFAIL earlier and wanted to check whether downgrading fixes it. */
2417 return dns_server_dnssec_supported(t
->server
);
2420 static bool dns_transaction_dnssec_supported_full(DnsTransaction
*t
) {
2425 /* Checks whether our transaction our any of the auxiliary transactions couldn't do DNSSEC. */
2427 if (!dns_transaction_dnssec_supported(t
))
2430 SET_FOREACH(dt
, t
->dnssec_transactions
)
2431 if (!dns_transaction_dnssec_supported(dt
))
2437 int dns_transaction_request_dnssec_keys(DnsTransaction
*t
) {
2438 DnsResourceRecord
*rr
;
2445 * Retrieve all auxiliary RRs for the answer we got, so that
2446 * we can verify signatures or prove that RRs are rightfully
2447 * unsigned. Specifically:
2449 * - For RRSIG we get the matching DNSKEY
2450 * - For DNSKEY we get the matching DS
2451 * - For unsigned SOA/NS we get the matching DS
2452 * - For unsigned CNAME/DNAME/DS we get the parent SOA RR
2453 * - For other unsigned RRs we get the matching SOA RR
2454 * - For SOA/NS queries with no matching response RR, and no NSEC/NSEC3, the DS RR
2455 * - For DS queries with no matching response RRs, and no NSEC/NSEC3, the parent's SOA RR
2456 * - For other queries with no matching response RRs, and no NSEC/NSEC3, the SOA RR
2459 if (FLAGS_SET(t
->query_flags
, SD_RESOLVED_NO_VALIDATE
) || t
->scope
->dnssec_mode
== DNSSEC_NO
)
2461 if (t
->answer_source
!= DNS_TRANSACTION_NETWORK
)
2462 return 0; /* We only need to validate stuff from the network */
2463 if (!dns_transaction_dnssec_supported(t
))
2464 return 0; /* If we can't do DNSSEC anyway there's no point in getting the auxiliary RRs */
2466 DNS_ANSWER_FOREACH(rr
, t
->answer
) {
2468 if (dns_type_is_pseudo(rr
->key
->type
))
2471 /* If this RR is in the negative trust anchor, we don't need to validate it. */
2472 r
= dns_transaction_negative_trust_anchor_lookup(t
, dns_resource_key_name(rr
->key
));
2478 switch (rr
->key
->type
) {
2480 case DNS_TYPE_RRSIG
: {
2481 /* For each RRSIG we request the matching DNSKEY */
2482 _cleanup_(dns_resource_key_unrefp
) DnsResourceKey
*dnskey
= NULL
;
2484 /* If this RRSIG is about a DNSKEY RR and the
2485 * signer is the same as the owner, then we
2486 * already have the DNSKEY, and we don't have
2487 * to look for more. */
2488 if (rr
->rrsig
.type_covered
== DNS_TYPE_DNSKEY
) {
2489 r
= dns_name_equal(rr
->rrsig
.signer
, dns_resource_key_name(rr
->key
));
2496 /* If the signer is not a parent of our
2497 * original query, then this is about an
2498 * auxiliary RRset, but not anything we asked
2499 * for. In this case we aren't interested,
2500 * because we don't want to request additional
2501 * RRs for stuff we didn't really ask for, and
2502 * also to avoid request loops, where
2503 * additional RRs from one transaction result
2504 * in another transaction whose additional RRs
2505 * point back to the original transaction, and
2507 r
= dns_name_endswith(dns_resource_key_name(dns_transaction_key(t
)), rr
->rrsig
.signer
);
2513 dnskey
= dns_resource_key_new(rr
->key
->class, DNS_TYPE_DNSKEY
, rr
->rrsig
.signer
);
2517 log_debug("Requesting DNSKEY to validate transaction %" PRIu16
" (%s, RRSIG with key tag: %" PRIu16
").",
2518 t
->id
, dns_resource_key_name(rr
->key
), rr
->rrsig
.key_tag
);
2519 r
= dns_transaction_request_dnssec_rr(t
, dnskey
);
2525 case DNS_TYPE_DNSKEY
: {
2526 /* For each DNSKEY we request the matching DS */
2527 _cleanup_(dns_resource_key_unrefp
) DnsResourceKey
*ds
= NULL
;
2529 /* If the DNSKEY we are looking at is not for
2530 * zone we are interested in, nor any of its
2531 * parents, we aren't interested, and don't
2532 * request it. After all, we don't want to end
2533 * up in request loops, and want to keep
2534 * additional traffic down. */
2536 r
= dns_name_endswith(dns_resource_key_name(dns_transaction_key(t
)), dns_resource_key_name(rr
->key
));
2542 ds
= dns_resource_key_new(rr
->key
->class, DNS_TYPE_DS
, dns_resource_key_name(rr
->key
));
2546 log_debug("Requesting DS to validate transaction %" PRIu16
" (%s, DNSKEY with key tag: %" PRIu16
").",
2547 t
->id
, dns_resource_key_name(rr
->key
), dnssec_keytag(rr
, false));
2548 r
= dns_transaction_request_dnssec_rr(t
, ds
);
2557 _cleanup_(dns_resource_key_unrefp
) DnsResourceKey
*ds
= NULL
;
2559 /* For an unsigned SOA or NS, try to acquire
2560 * the matching DS RR, as we are at a zone cut
2561 * then, and whether a DS exists tells us
2562 * whether the zone is signed. Do so only if
2563 * this RR matches our original question,
2566 r
= dns_resource_key_match_rr(dns_transaction_key(t
), rr
, NULL
);
2570 /* Hmm, so this SOA RR doesn't match our original question. In this case, maybe this is
2571 * a negative reply, and we need the SOA RR's TTL in order to cache a negative entry?
2572 * If so, we need to validate it, too. */
2574 r
= dns_answer_match_key(t
->answer
, dns_transaction_key(t
), NULL
);
2577 if (r
> 0) /* positive reply, we won't need the SOA and hence don't need to validate
2581 /* Only bother with this if the SOA/NS RR we are looking at is actually a parent of
2582 * what we are looking for, otherwise there's no value in it for us. */
2583 r
= dns_name_endswith(dns_resource_key_name(dns_transaction_key(t
)), dns_resource_key_name(rr
->key
));
2590 r
= dnssec_has_rrsig(t
->answer
, rr
->key
);
2596 ds
= dns_resource_key_new(rr
->key
->class, DNS_TYPE_DS
, dns_resource_key_name(rr
->key
));
2600 log_debug("Requesting DS to validate transaction %" PRIu16
" (%s, unsigned SOA/NS RRset).",
2601 t
->id
, dns_resource_key_name(rr
->key
));
2602 r
= dns_transaction_request_dnssec_rr(t
, ds
);
2610 case DNS_TYPE_CNAME
:
2611 case DNS_TYPE_DNAME
: {
2612 _cleanup_(dns_resource_key_unrefp
) DnsResourceKey
*soa
= NULL
;
2615 /* CNAMEs and DNAMEs cannot be located at a
2616 * zone apex, hence ask for the parent SOA for
2617 * unsigned CNAME/DNAME RRs, maybe that's the
2618 * apex. But do all that only if this is
2619 * actually a response to our original
2622 * Similar for DS RRs, which are signed when
2623 * the parent SOA is signed. */
2625 r
= dns_transaction_is_primary_response(t
, rr
);
2631 r
= dnssec_has_rrsig(t
->answer
, rr
->key
);
2637 r
= dns_answer_has_dname_for_cname(t
->answer
, rr
);
2643 name
= dns_resource_key_name(rr
->key
);
2644 r
= dns_name_parent(&name
);
2650 soa
= dns_resource_key_new(rr
->key
->class, DNS_TYPE_SOA
, name
);
2654 log_debug("Requesting parent SOA to validate transaction %" PRIu16
" (%s, unsigned CNAME/DNAME/DS RRset).",
2655 t
->id
, dns_resource_key_name(rr
->key
));
2656 r
= dns_transaction_request_dnssec_rr(t
, soa
);
2664 _cleanup_(dns_resource_key_unrefp
) DnsResourceKey
*soa
= NULL
;
2666 /* For other unsigned RRsets (including
2667 * NSEC/NSEC3!), look for proof the zone is
2668 * unsigned, by requesting the SOA RR of the
2669 * zone. However, do so only if they are
2670 * directly relevant to our original
2673 r
= dns_transaction_is_primary_response(t
, rr
);
2679 r
= dnssec_has_rrsig(t
->answer
, rr
->key
);
2685 soa
= dns_resource_key_new(rr
->key
->class, DNS_TYPE_SOA
, dns_resource_key_name(rr
->key
));
2689 log_debug("Requesting SOA to validate transaction %" PRIu16
" (%s, unsigned non-SOA/NS RRset <%s>).",
2690 t
->id
, dns_resource_key_name(rr
->key
), dns_resource_record_to_string(rr
));
2691 r
= dns_transaction_request_dnssec_rr(t
, soa
);
2698 /* Above, we requested everything necessary to validate what
2699 * we got. Now, let's request what we need to validate what we
2702 r
= dns_transaction_has_negative_answer(t
);
2706 const char *name
, *signed_status
;
2709 name
= dns_resource_key_name(dns_transaction_key(t
));
2710 signed_status
= dns_answer_contains_nsec_or_nsec3(t
->answer
) ? "signed" : "unsigned";
2712 /* If this was a SOA or NS request, then check if there's a DS RR for the same domain. Note that this
2713 * could also be used as indication that we are not at a zone apex, but in real world setups there are
2714 * too many broken DNS servers (Hello, incapdns.net!) where non-terminal zones return NXDOMAIN even
2715 * though they have further children. If this was a DS request, then it's signed when the parent zone
2716 * is signed, hence ask the parent SOA in that case. If this was any other RR then ask for the SOA RR,
2717 * to see if that is signed. */
2719 if (dns_transaction_key(t
)->type
== DNS_TYPE_DS
) {
2720 r
= dns_name_parent(&name
);
2722 type
= DNS_TYPE_SOA
;
2723 log_debug("Requesting parent SOA (%s %s) to validate transaction %" PRIu16
" (%s, %s empty DS response).",
2724 special_glyph(SPECIAL_GLYPH_ARROW_RIGHT
), name
, t
->id
,
2725 dns_resource_key_name(dns_transaction_key(t
)), signed_status
);
2729 } else if (IN_SET(dns_transaction_key(t
)->type
, DNS_TYPE_SOA
, DNS_TYPE_NS
)) {
2732 log_debug("Requesting DS (%s %s) to validate transaction %" PRIu16
" (%s, %s empty SOA/NS response).",
2733 special_glyph(SPECIAL_GLYPH_ARROW_RIGHT
), name
, t
->id
, name
, signed_status
);
2736 type
= DNS_TYPE_SOA
;
2737 log_debug("Requesting SOA (%s %s) to validate transaction %" PRIu16
" (%s, %s empty non-SOA/NS/DS response).",
2738 special_glyph(SPECIAL_GLYPH_ARROW_RIGHT
), name
, t
->id
, name
, signed_status
);
2742 _cleanup_(dns_resource_key_unrefp
) DnsResourceKey
*soa
= NULL
;
2744 soa
= dns_resource_key_new(dns_transaction_key(t
)->class, type
, name
);
2748 r
= dns_transaction_request_dnssec_rr(t
, soa
);
2754 return dns_transaction_dnssec_is_live(t
);
2757 void dns_transaction_notify(DnsTransaction
*t
, DnsTransaction
*source
) {
2761 /* Invoked whenever any of our auxiliary DNSSEC transactions completed its work. If the state is still PENDING,
2762 we are still in the loop that adds further DNSSEC transactions, hence don't check if we are ready yet. If
2763 the state is VALIDATING however, we should check if we are complete now. */
2765 if (t
->state
== DNS_TRANSACTION_VALIDATING
)
2766 dns_transaction_process_dnssec(t
);
2769 static int dns_transaction_validate_dnskey_by_ds(DnsTransaction
*t
) {
2770 DnsAnswerItem
*item
;
2775 /* Add all DNSKEY RRs from the answer that are validated by DS
2776 * RRs from the list of validated keys to the list of
2777 * validated keys. */
2779 DNS_ANSWER_FOREACH_ITEM(item
, t
->answer
) {
2781 r
= dnssec_verify_dnskey_by_ds_search(item
->rr
, t
->validated_keys
);
2787 /* If so, the DNSKEY is validated too. */
2788 r
= dns_answer_add_extend(&t
->validated_keys
, item
->rr
, item
->ifindex
, item
->flags
|DNS_ANSWER_AUTHENTICATED
, item
->rrsig
);
2796 static int dns_transaction_requires_rrsig(DnsTransaction
*t
, DnsResourceRecord
*rr
) {
2802 /* Checks if the RR we are looking for must be signed with an
2803 * RRSIG. This is used for positive responses. */
2805 if (t
->scope
->dnssec_mode
== DNSSEC_NO
)
2808 if (dns_type_is_pseudo(rr
->key
->type
))
2811 r
= dns_transaction_negative_trust_anchor_lookup(t
, dns_resource_key_name(rr
->key
));
2817 switch (rr
->key
->type
) {
2819 case DNS_TYPE_RRSIG
:
2820 /* RRSIGs are the signatures themselves, they need no signing. */
2827 /* For SOA or NS RRs we look for a matching DS transaction */
2829 SET_FOREACH(dt
, t
->dnssec_transactions
) {
2831 if (dns_transaction_key(dt
)->class != rr
->key
->class)
2833 if (dns_transaction_key(dt
)->type
!= DNS_TYPE_DS
)
2836 r
= dns_name_equal(dns_resource_key_name(dns_transaction_key(dt
)), dns_resource_key_name(rr
->key
));
2842 /* We found a DS transactions for the SOA/NS
2843 * RRs we are looking at. If it discovered signed DS
2844 * RRs, then we need to be signed, too. */
2846 if (!FLAGS_SET(dt
->answer_query_flags
, SD_RESOLVED_AUTHENTICATED
))
2849 return dns_answer_match_key(dt
->answer
, dns_transaction_key(dt
), NULL
);
2852 /* We found nothing that proves this is safe to leave
2853 * this unauthenticated, hence ask inist on
2854 * authentication. */
2859 case DNS_TYPE_CNAME
:
2860 case DNS_TYPE_DNAME
: {
2861 const char *parent
= NULL
;
2865 * CNAME/DNAME RRs cannot be located at a zone apex, hence look directly for the parent SOA.
2867 * DS RRs are signed if the parent is signed, hence also look at the parent SOA
2870 SET_FOREACH(dt
, t
->dnssec_transactions
) {
2872 if (dns_transaction_key(dt
)->class != rr
->key
->class)
2874 if (dns_transaction_key(dt
)->type
!= DNS_TYPE_SOA
)
2878 parent
= dns_resource_key_name(rr
->key
);
2879 r
= dns_name_parent(&parent
);
2883 if (rr
->key
->type
== DNS_TYPE_DS
)
2886 /* A CNAME/DNAME without a parent? That's sooo weird. */
2887 return log_debug_errno(SYNTHETIC_ERRNO(EBADMSG
),
2888 "Transaction %" PRIu16
" claims CNAME/DNAME at root. Refusing.", t
->id
);
2892 r
= dns_name_equal(dns_resource_key_name(dns_transaction_key(dt
)), parent
);
2898 return FLAGS_SET(dt
->answer_query_flags
, SD_RESOLVED_AUTHENTICATED
);
2907 /* Any other kind of RR (including DNSKEY/NSEC/NSEC3). Let's see if our SOA lookup was authenticated */
2909 SET_FOREACH(dt
, t
->dnssec_transactions
) {
2911 if (dns_transaction_key(dt
)->class != rr
->key
->class)
2913 if (dns_transaction_key(dt
)->type
!= DNS_TYPE_SOA
)
2916 r
= dns_name_equal(dns_resource_key_name(dns_transaction_key(dt
)), dns_resource_key_name(rr
->key
));
2922 /* We found the transaction that was supposed to find the SOA RR for us. It was
2923 * successful, but found no RR for us. This means we are not at a zone cut. In this
2924 * case, we require authentication if the SOA lookup was authenticated too. */
2925 return FLAGS_SET(dt
->answer_query_flags
, SD_RESOLVED_AUTHENTICATED
);
2932 static int dns_transaction_in_private_tld(DnsTransaction
*t
, const DnsResourceKey
*key
) {
2937 /* If DNSSEC downgrade mode is on, checks whether the
2938 * specified RR is one level below a TLD we have proven not to
2939 * exist. In such a case we assume that this is a private
2940 * domain, and permit it.
2942 * This detects cases like the Fritz!Box router networks. Each
2943 * Fritz!Box router serves a private "fritz.box" zone, in the
2944 * non-existing TLD "box". Requests for the "fritz.box" domain
2945 * are served by the router itself, while requests for the
2946 * "box" domain will result in NXDOMAIN.
2948 * Note that this logic is unable to detect cases where a
2949 * router serves a private DNS zone directly under
2950 * non-existing TLD. In such a case we cannot detect whether
2951 * the TLD is supposed to exist or not, as all requests we
2952 * make for it will be answered by the router's zone, and not
2953 * by the root zone. */
2957 if (t
->scope
->dnssec_mode
!= DNSSEC_ALLOW_DOWNGRADE
)
2958 return false; /* In strict DNSSEC mode what doesn't exist, doesn't exist */
2960 tld
= dns_resource_key_name(key
);
2961 r
= dns_name_parent(&tld
);
2965 return false; /* Already the root domain */
2967 if (!dns_name_is_single_label(tld
))
2970 SET_FOREACH(dt
, t
->dnssec_transactions
) {
2972 if (dns_transaction_key(dt
)->class != key
->class)
2975 r
= dns_name_equal(dns_resource_key_name(dns_transaction_key(dt
)), tld
);
2981 /* We found an auxiliary lookup we did for the TLD. If
2982 * that returned with NXDOMAIN, we know the TLD didn't
2983 * exist, and hence this might be a private zone. */
2985 return dt
->answer_rcode
== DNS_RCODE_NXDOMAIN
;
2991 static int dns_transaction_requires_nsec(DnsTransaction
*t
) {
2992 char key_str
[DNS_RESOURCE_KEY_STRING_MAX
];
3000 /* Checks if we need to insist on NSEC/NSEC3 RRs for proving
3001 * this negative reply */
3003 if (t
->scope
->dnssec_mode
== DNSSEC_NO
)
3006 if (dns_type_is_pseudo(dns_transaction_key(t
)->type
))
3009 r
= dns_transaction_negative_trust_anchor_lookup(t
, dns_resource_key_name(dns_transaction_key(t
)));
3015 r
= dns_transaction_in_private_tld(t
, dns_transaction_key(t
));
3019 /* The lookup is from a TLD that is proven not to
3020 * exist, and we are in downgrade mode, hence ignore
3021 * that fact that we didn't get any NSEC RRs. */
3023 log_info("Detected a negative query %s in a private DNS zone, permitting unsigned response.",
3024 dns_resource_key_to_string(dns_transaction_key(t
), key_str
, sizeof key_str
));
3028 name
= dns_resource_key_name(dns_transaction_key(t
));
3030 if (dns_transaction_key(t
)->type
== DNS_TYPE_DS
) {
3032 /* We got a negative reply for this DS lookup? DS RRs are signed when their parent zone is signed,
3033 * hence check the parent SOA in this case. */
3035 r
= dns_name_parent(&name
);
3041 type
= DNS_TYPE_SOA
;
3043 } else if (IN_SET(dns_transaction_key(t
)->type
, DNS_TYPE_SOA
, DNS_TYPE_NS
))
3044 /* We got a negative reply for this SOA/NS lookup? If so, check if there's a DS RR for this */
3047 /* For all other negative replies, check for the SOA lookup */
3048 type
= DNS_TYPE_SOA
;
3050 /* For all other RRs we check the SOA on the same level to see
3051 * if it's signed. */
3053 SET_FOREACH(dt
, t
->dnssec_transactions
) {
3055 if (dns_transaction_key(dt
)->class != dns_transaction_key(t
)->class)
3057 if (dns_transaction_key(dt
)->type
!= type
)
3060 r
= dns_name_equal(dns_resource_key_name(dns_transaction_key(dt
)), name
);
3066 return FLAGS_SET(dt
->answer_query_flags
, SD_RESOLVED_AUTHENTICATED
);
3069 /* If in doubt, require NSEC/NSEC3 */
3073 static int dns_transaction_dnskey_authenticated(DnsTransaction
*t
, DnsResourceRecord
*rr
) {
3074 DnsResourceRecord
*rrsig
;
3078 /* Checks whether any of the DNSKEYs used for the RRSIGs for
3079 * the specified RRset is authenticated (i.e. has a matching
3082 r
= dns_transaction_negative_trust_anchor_lookup(t
, dns_resource_key_name(rr
->key
));
3088 DNS_ANSWER_FOREACH(rrsig
, t
->answer
) {
3091 r
= dnssec_key_match_rrsig(rr
->key
, rrsig
);
3097 SET_FOREACH(dt
, t
->dnssec_transactions
) {
3099 if (dns_transaction_key(dt
)->class != rr
->key
->class)
3102 if (dns_transaction_key(dt
)->type
== DNS_TYPE_DNSKEY
) {
3104 r
= dns_name_equal(dns_resource_key_name(dns_transaction_key(dt
)), rrsig
->rrsig
.signer
);
3110 /* OK, we found an auxiliary DNSKEY lookup. If that lookup is authenticated,
3113 if (FLAGS_SET(dt
->answer_query_flags
, SD_RESOLVED_AUTHENTICATED
))
3118 } else if (dns_transaction_key(dt
)->type
== DNS_TYPE_DS
) {
3120 r
= dns_name_equal(dns_resource_key_name(dns_transaction_key(dt
)), rrsig
->rrsig
.signer
);
3126 /* OK, we found an auxiliary DS lookup. If that lookup is authenticated and
3127 * non-zero, we won! */
3129 if (!FLAGS_SET(dt
->answer_query_flags
, SD_RESOLVED_AUTHENTICATED
))
3132 return dns_answer_match_key(dt
->answer
, dns_transaction_key(dt
), NULL
);
3137 return found
? false : -ENXIO
;
3140 static int dns_transaction_known_signed(DnsTransaction
*t
, DnsResourceRecord
*rr
) {
3144 /* We know that the root domain is signed, hence if it appears
3145 * not to be signed, there's a problem with the DNS server */
3147 return rr
->key
->class == DNS_CLASS_IN
&&
3148 dns_name_is_root(dns_resource_key_name(rr
->key
));
3151 static int dns_transaction_check_revoked_trust_anchors(DnsTransaction
*t
) {
3152 DnsResourceRecord
*rr
;
3157 /* Maybe warn the user that we encountered a revoked DNSKEY
3158 * for a key from our trust anchor. Note that we don't care
3159 * whether the DNSKEY can be authenticated or not. It's
3160 * sufficient if it is self-signed. */
3162 DNS_ANSWER_FOREACH(rr
, t
->answer
) {
3163 r
= dns_trust_anchor_check_revoked(&t
->scope
->manager
->trust_anchor
, rr
, t
->answer
);
3171 static int dns_transaction_invalidate_revoked_keys(DnsTransaction
*t
) {
3177 /* Removes all DNSKEY/DS objects from t->validated_keys that
3178 * our trust anchors database considers revoked. */
3181 DnsResourceRecord
*rr
;
3185 DNS_ANSWER_FOREACH(rr
, t
->validated_keys
) {
3186 r
= dns_trust_anchor_is_revoked(&t
->scope
->manager
->trust_anchor
, rr
);
3190 r
= dns_answer_remove_by_rr(&t
->validated_keys
, rr
);
3204 static int dns_transaction_copy_validated(DnsTransaction
*t
) {
3210 /* Copy all validated RRs from the auxiliary DNSSEC transactions into our set of validated RRs */
3212 SET_FOREACH(dt
, t
->dnssec_transactions
) {
3214 if (DNS_TRANSACTION_IS_LIVE(dt
->state
))
3217 if (!FLAGS_SET(dt
->answer_query_flags
, SD_RESOLVED_AUTHENTICATED
))
3220 r
= dns_answer_extend(&t
->validated_keys
, dt
->answer
);
3229 DNSSEC_PHASE_DNSKEY
, /* Phase #1, only validate DNSKEYs */
3230 DNSSEC_PHASE_NSEC
, /* Phase #2, only validate NSEC+NSEC3 */
3231 DNSSEC_PHASE_ALL
, /* Phase #3, validate everything else */
3234 static int dnssec_validate_records(
3238 unsigned *nvalidations
,
3239 DnsAnswer
**validated
) {
3241 DnsResourceRecord
*rr
;
3244 assert(nvalidations
);
3246 /* Returns negative on error, 0 if validation failed, 1 to restart validation, 2 when finished. */
3248 DNS_ANSWER_FOREACH(rr
, t
->answer
) {
3249 _unused_
_cleanup_(dns_resource_record_unrefp
) DnsResourceRecord
*rr_ref
= dns_resource_record_ref(rr
);
3250 DnsResourceRecord
*rrsig
= NULL
;
3251 DnssecResult result
;
3253 switch (rr
->key
->type
) {
3254 case DNS_TYPE_RRSIG
:
3257 case DNS_TYPE_DNSKEY
:
3258 /* We validate DNSKEYs only in the DNSKEY and ALL phases */
3259 if (phase
== DNSSEC_PHASE_NSEC
)
3264 case DNS_TYPE_NSEC3
:
3267 /* We validate NSEC/NSEC3 only in the NSEC and ALL phases */
3268 if (phase
== DNSSEC_PHASE_DNSKEY
)
3273 /* We validate all other RRs only in the ALL phases */
3274 if (phase
!= DNSSEC_PHASE_ALL
)
3278 r
= dnssec_verify_rrset_search(
3289 log_debug("Looking at %s: %s", strna(dns_resource_record_to_string(rr
)), dnssec_result_to_string(result
));
3291 if (result
== DNSSEC_VALIDATED
) {
3294 if (rr
->key
->type
== DNS_TYPE_DNSKEY
) {
3295 /* If we just validated a DNSKEY RRset, then let's add these keys to
3296 * the set of validated keys for this transaction. */
3298 r
= dns_answer_copy_by_key(&t
->validated_keys
, t
->answer
, rr
->key
, DNS_ANSWER_AUTHENTICATED
, rrsig
);
3302 /* Some of the DNSKEYs we just added might already have been revoked,
3303 * remove them again in that case. */
3304 r
= dns_transaction_invalidate_revoked_keys(t
);
3309 /* Add the validated RRset to the new list of validated RRsets, and remove it from
3310 * the unvalidated RRsets. We mark the RRset as authenticated and cacheable. */
3311 r
= dns_answer_move_by_key(validated
, &t
->answer
, rr
->key
, DNS_ANSWER_AUTHENTICATED
|DNS_ANSWER_CACHEABLE
, rrsig
);
3315 manager_dnssec_verdict(t
->scope
->manager
, DNSSEC_SECURE
, rr
->key
);
3317 /* Exit the loop, we dropped something from the answer, start from the beginning */
3321 /* If we haven't read all DNSKEYs yet a negative result of the validation is irrelevant, as
3322 * there might be more DNSKEYs coming. Similar, if we haven't read all NSEC/NSEC3 RRs yet,
3323 * we cannot do positive wildcard proofs yet, as those require the NSEC/NSEC3 RRs. */
3324 if (phase
!= DNSSEC_PHASE_ALL
)
3327 if (result
== DNSSEC_VALIDATED_WILDCARD
) {
3328 bool authenticated
= false;
3333 /* This RRset validated, but as a wildcard. This means we need
3334 * to prove via NSEC/NSEC3 that no matching non-wildcard RR exists. */
3336 /* First step, determine the source of synthesis */
3337 r
= dns_resource_record_source(rrsig
, &source
);
3341 r
= dnssec_test_positive_wildcard(*validated
,
3342 dns_resource_key_name(rr
->key
),
3344 rrsig
->rrsig
.signer
,
3347 /* Unless the NSEC proof showed that the key really doesn't exist something is off. */
3349 result
= DNSSEC_INVALID
;
3351 r
= dns_answer_move_by_key(
3355 authenticated
? (DNS_ANSWER_AUTHENTICATED
|DNS_ANSWER_CACHEABLE
) : 0,
3360 manager_dnssec_verdict(t
->scope
->manager
, authenticated
? DNSSEC_SECURE
: DNSSEC_INSECURE
, rr
->key
);
3362 /* Exit the loop, we dropped something from the answer, start from the beginning */
3367 if (result
== DNSSEC_NO_SIGNATURE
) {
3368 r
= dns_transaction_requires_rrsig(t
, rr
);
3372 /* Data does not require signing. In that case, just copy it over,
3373 * but remember that this is by no means authenticated. */
3374 r
= dns_answer_move_by_key(
3383 manager_dnssec_verdict(t
->scope
->manager
, DNSSEC_INSECURE
, rr
->key
);
3387 r
= dns_transaction_known_signed(t
, rr
);
3391 /* This is an RR we know has to be signed. If it isn't this means
3392 * the server is not attaching RRSIGs, hence complain. */
3394 dns_server_packet_rrsig_missing(t
->server
, t
->current_feature_level
);
3396 if (t
->scope
->dnssec_mode
== DNSSEC_ALLOW_DOWNGRADE
) {
3398 /* Downgrading is OK? If so, just consider the information unsigned */
3400 r
= dns_answer_move_by_key(validated
, &t
->answer
, rr
->key
, 0, NULL
);
3404 manager_dnssec_verdict(t
->scope
->manager
, DNSSEC_INSECURE
, rr
->key
);
3408 /* Otherwise, fail */
3409 t
->answer_dnssec_result
= DNSSEC_INCOMPATIBLE_SERVER
;
3413 r
= dns_transaction_in_private_tld(t
, rr
->key
);
3417 char s
[DNS_RESOURCE_KEY_STRING_MAX
];
3419 /* The data is from a TLD that is proven not to exist, and we are in downgrade
3420 * mode, hence ignore the fact that this was not signed. */
3422 log_info("Detected RRset %s is in a private DNS zone, permitting unsigned RRs.",
3423 dns_resource_key_to_string(rr
->key
, s
, sizeof s
));
3425 r
= dns_answer_move_by_key(validated
, &t
->answer
, rr
->key
, 0, NULL
);
3429 manager_dnssec_verdict(t
->scope
->manager
, DNSSEC_INSECURE
, rr
->key
);
3434 /* https://datatracker.ietf.org/doc/html/rfc6840#section-5.2 */
3435 if (result
== DNSSEC_UNSUPPORTED_ALGORITHM
) {
3436 r
= dns_answer_move_by_key(validated
, &t
->answer
, rr
->key
, 0, NULL
);
3440 manager_dnssec_verdict(t
->scope
->manager
, DNSSEC_INSECURE
, rr
->key
);
3446 DNSSEC_SIGNATURE_EXPIRED
)) {
3448 r
= dns_transaction_dnskey_authenticated(t
, rr
);
3449 if (r
< 0 && r
!= -ENXIO
)
3452 /* The DNSKEY transaction was not authenticated, this means there's
3453 * no DS for this, which means it's OK if no keys are found for this signature. */
3455 r
= dns_answer_move_by_key(validated
, &t
->answer
, rr
->key
, 0, NULL
);
3459 manager_dnssec_verdict(t
->scope
->manager
, DNSSEC_INSECURE
, rr
->key
);
3464 r
= dns_transaction_is_primary_response(t
, rr
);
3468 /* Look for a matching DNAME for this CNAME */
3469 r
= dns_answer_has_dname_for_cname(t
->answer
, rr
);
3473 /* Also look among the stuff we already validated */
3474 r
= dns_answer_has_dname_for_cname(*validated
, rr
);
3482 DNSSEC_SIGNATURE_EXPIRED
,
3483 DNSSEC_NO_SIGNATURE
))
3484 manager_dnssec_verdict(t
->scope
->manager
, DNSSEC_BOGUS
, rr
->key
);
3485 else /* DNSSEC_MISSING_KEY, DNSSEC_UNSUPPORTED_ALGORITHM,
3486 or DNSSEC_TOO_MANY_VALIDATIONS */
3487 manager_dnssec_verdict(t
->scope
->manager
, DNSSEC_INDETERMINATE
, rr
->key
);
3489 /* This is a primary response to our question, and it failed validation.
3491 t
->answer_dnssec_result
= result
;
3495 /* This is a primary response, but we do have a DNAME RR
3496 * in the RR that can replay this CNAME, hence rely on
3497 * that, and we can remove the CNAME in favour of it. */
3500 /* This is just some auxiliary data. Just remove the RRset and continue. */
3501 r
= dns_answer_remove_by_key(&t
->answer
, rr
->key
);
3505 /* We dropped something from the answer, start from the beginning. */
3509 return 2; /* Finito. */
3512 int dns_transaction_validate_dnssec(DnsTransaction
*t
) {
3513 _cleanup_(dns_answer_unrefp
) DnsAnswer
*validated
= NULL
;
3515 DnsAnswerFlags flags
;
3517 char key_str
[DNS_RESOURCE_KEY_STRING_MAX
];
3521 /* We have now collected all DS and DNSKEY RRs in t->validated_keys, let's see which RRs we can now
3522 * authenticate with that. */
3524 if (FLAGS_SET(t
->query_flags
, SD_RESOLVED_NO_VALIDATE
) || t
->scope
->dnssec_mode
== DNSSEC_NO
)
3527 /* Already validated */
3528 if (t
->answer_dnssec_result
!= _DNSSEC_RESULT_INVALID
)
3531 /* Our own stuff needs no validation */
3532 if (IN_SET(t
->answer_source
, DNS_TRANSACTION_ZONE
, DNS_TRANSACTION_TRUST_ANCHOR
)) {
3533 t
->answer_dnssec_result
= DNSSEC_VALIDATED
;
3534 SET_FLAG(t
->answer_query_flags
, SD_RESOLVED_AUTHENTICATED
, true);
3538 /* Cached stuff is not affected by validation. */
3539 if (t
->answer_source
!= DNS_TRANSACTION_NETWORK
)
3542 if (!dns_transaction_dnssec_supported_full(t
)) {
3543 /* The server does not support DNSSEC, or doesn't augment responses with RRSIGs. */
3544 t
->answer_dnssec_result
= DNSSEC_INCOMPATIBLE_SERVER
;
3545 log_debug("Not validating response for %" PRIu16
", used server feature level does not support DNSSEC.", t
->id
);
3549 log_debug("Validating response from transaction %" PRIu16
" (%s).",
3551 dns_resource_key_to_string(dns_transaction_key(t
), key_str
, sizeof key_str
));
3553 /* First, see if this response contains any revoked trust
3554 * anchors we care about */
3555 r
= dns_transaction_check_revoked_trust_anchors(t
);
3559 /* Third, copy all RRs we acquired successfully from auxiliary RRs over. */
3560 r
= dns_transaction_copy_validated(t
);
3564 /* Second, see if there are DNSKEYs we already know a
3565 * validated DS for. */
3566 r
= dns_transaction_validate_dnskey_by_ds(t
);
3570 /* Fourth, remove all DNSKEY and DS RRs again that our trust
3571 * anchor says are revoked. After all we might have marked
3572 * some keys revoked above, but they might still be lingering
3573 * in our validated_keys list. */
3574 r
= dns_transaction_invalidate_revoked_keys(t
);
3578 phase
= DNSSEC_PHASE_DNSKEY
;
3579 for (unsigned nvalidations
= 0;;) {
3580 bool have_nsec
= false;
3582 r
= dnssec_validate_records(t
, phase
, &have_nsec
, &nvalidations
, &validated
);
3586 if (nvalidations
> DNSSEC_VALIDATION_MAX
) {
3587 /* This reply requires an onerous number of signature validations to verify. Let's
3588 * not waste our time trying, as this shouldn't happen for well-behaved domains
3590 t
->answer_dnssec_result
= DNSSEC_TOO_MANY_VALIDATIONS
;
3594 /* Try again as long as we managed to achieve something */
3598 if (phase
== DNSSEC_PHASE_DNSKEY
&& have_nsec
) {
3599 /* OK, we processed all DNSKEYs, and there are NSEC/NSEC3 RRs, look at those now. */
3600 phase
= DNSSEC_PHASE_NSEC
;
3604 if (phase
!= DNSSEC_PHASE_ALL
) {
3605 /* OK, we processed all DNSKEYs and NSEC/NSEC3 RRs, look at all the rest now.
3606 * Note that in this third phase we start to remove RRs we couldn't validate. */
3607 phase
= DNSSEC_PHASE_ALL
;
3615 DNS_ANSWER_REPLACE(t
->answer
, TAKE_PTR(validated
));
3617 /* At this point the answer only contains validated
3618 * RRsets. Now, let's see if it actually answers the question
3619 * we asked. If so, great! If it doesn't, then see if
3620 * NSEC/NSEC3 can prove this. */
3621 r
= dns_transaction_has_positive_answer(t
, &flags
);
3623 /* Yes, it answers the question! */
3625 if (flags
& DNS_ANSWER_AUTHENTICATED
) {
3626 /* The answer is fully authenticated, yay. */
3627 t
->answer_dnssec_result
= DNSSEC_VALIDATED
;
3628 t
->answer_rcode
= DNS_RCODE_SUCCESS
;
3629 SET_FLAG(t
->answer_query_flags
, SD_RESOLVED_AUTHENTICATED
, true);
3631 /* The answer is not fully authenticated. */
3632 t
->answer_dnssec_result
= DNSSEC_UNSIGNED
;
3633 SET_FLAG(t
->answer_query_flags
, SD_RESOLVED_AUTHENTICATED
, false);
3636 } else if (r
== 0) {
3637 DnssecNsecResult nr
;
3638 bool authenticated
= false;
3640 /* Bummer! Let's check NSEC/NSEC3 */
3641 r
= dnssec_nsec_test(t
->answer
, dns_transaction_key(t
), &nr
, &authenticated
, &t
->answer_nsec_ttl
);
3647 case DNSSEC_NSEC_NXDOMAIN
:
3648 /* NSEC proves the domain doesn't exist. Very good. */
3649 log_debug("Proved NXDOMAIN via NSEC/NSEC3 for transaction %u (%s)", t
->id
, key_str
);
3650 t
->answer_dnssec_result
= DNSSEC_VALIDATED
;
3651 t
->answer_rcode
= DNS_RCODE_NXDOMAIN
;
3652 SET_FLAG(t
->answer_query_flags
, SD_RESOLVED_AUTHENTICATED
, authenticated
);
3654 manager_dnssec_verdict(t
->scope
->manager
, authenticated
? DNSSEC_SECURE
: DNSSEC_INSECURE
, dns_transaction_key(t
));
3657 case DNSSEC_NSEC_NODATA
:
3658 /* NSEC proves that there's no data here, very good. */
3659 log_debug("Proved NODATA via NSEC/NSEC3 for transaction %u (%s)", t
->id
, key_str
);
3660 t
->answer_dnssec_result
= DNSSEC_VALIDATED
;
3661 t
->answer_rcode
= DNS_RCODE_SUCCESS
;
3662 SET_FLAG(t
->answer_query_flags
, SD_RESOLVED_AUTHENTICATED
, authenticated
);
3664 manager_dnssec_verdict(t
->scope
->manager
, authenticated
? DNSSEC_SECURE
: DNSSEC_INSECURE
, dns_transaction_key(t
));
3667 case DNSSEC_NSEC_OPTOUT
:
3668 /* NSEC3 says the data might not be signed */
3669 log_debug("Data is NSEC3 opt-out via NSEC/NSEC3 for transaction %u (%s)", t
->id
, key_str
);
3670 t
->answer_dnssec_result
= DNSSEC_UNSIGNED
;
3671 SET_FLAG(t
->answer_query_flags
, SD_RESOLVED_AUTHENTICATED
, false);
3673 manager_dnssec_verdict(t
->scope
->manager
, DNSSEC_INSECURE
, dns_transaction_key(t
));
3676 case DNSSEC_NSEC_NO_RR
:
3677 /* No NSEC data? Bummer! */
3679 r
= dns_transaction_requires_nsec(t
);
3683 t
->answer_dnssec_result
= DNSSEC_NO_SIGNATURE
;
3684 manager_dnssec_verdict(t
->scope
->manager
, DNSSEC_BOGUS
, dns_transaction_key(t
));
3686 t
->answer_dnssec_result
= DNSSEC_UNSIGNED
;
3687 SET_FLAG(t
->answer_query_flags
, SD_RESOLVED_AUTHENTICATED
, false);
3688 manager_dnssec_verdict(t
->scope
->manager
, DNSSEC_INSECURE
, dns_transaction_key(t
));
3693 case DNSSEC_NSEC_UNSUPPORTED_ALGORITHM
:
3694 /* We don't know the NSEC3 algorithm used? */
3695 t
->answer_dnssec_result
= DNSSEC_UNSUPPORTED_ALGORITHM
;
3696 manager_dnssec_verdict(t
->scope
->manager
, DNSSEC_INDETERMINATE
, dns_transaction_key(t
));
3699 case DNSSEC_NSEC_FOUND
:
3700 case DNSSEC_NSEC_CNAME
:
3701 /* NSEC says it needs to be there, but we couldn't find it? Bummer! */
3702 t
->answer_dnssec_result
= DNSSEC_NSEC_MISMATCH
;
3703 manager_dnssec_verdict(t
->scope
->manager
, DNSSEC_BOGUS
, dns_transaction_key(t
));
3707 assert_not_reached();
3714 static const char* const dns_transaction_state_table
[_DNS_TRANSACTION_STATE_MAX
] = {
3715 [DNS_TRANSACTION_NULL
] = "null",
3716 [DNS_TRANSACTION_PENDING
] = "pending",
3717 [DNS_TRANSACTION_VALIDATING
] = "validating",
3718 [DNS_TRANSACTION_RCODE_FAILURE
] = "rcode-failure",
3719 [DNS_TRANSACTION_SUCCESS
] = "success",
3720 [DNS_TRANSACTION_NO_SERVERS
] = "no-servers",
3721 [DNS_TRANSACTION_TIMEOUT
] = "timeout",
3722 [DNS_TRANSACTION_ATTEMPTS_MAX_REACHED
] = "attempts-max-reached",
3723 [DNS_TRANSACTION_INVALID_REPLY
] = "invalid-reply",
3724 [DNS_TRANSACTION_ERRNO
] = "errno",
3725 [DNS_TRANSACTION_ABORTED
] = "aborted",
3726 [DNS_TRANSACTION_DNSSEC_FAILED
] = "dnssec-failed",
3727 [DNS_TRANSACTION_NO_TRUST_ANCHOR
] = "no-trust-anchor",
3728 [DNS_TRANSACTION_RR_TYPE_UNSUPPORTED
] = "rr-type-unsupported",
3729 [DNS_TRANSACTION_NETWORK_DOWN
] = "network-down",
3730 [DNS_TRANSACTION_NOT_FOUND
] = "not-found",
3731 [DNS_TRANSACTION_NO_SOURCE
] = "no-source",
3732 [DNS_TRANSACTION_STUB_LOOP
] = "stub-loop",
3734 DEFINE_STRING_TABLE_LOOKUP(dns_transaction_state
, DnsTransactionState
);
3736 static const char* const dns_transaction_source_table
[_DNS_TRANSACTION_SOURCE_MAX
] = {
3737 [DNS_TRANSACTION_NETWORK
] = "network",
3738 [DNS_TRANSACTION_CACHE
] = "cache",
3739 [DNS_TRANSACTION_ZONE
] = "zone",
3740 [DNS_TRANSACTION_TRUST_ANCHOR
] = "trust-anchor",
3742 DEFINE_STRING_TABLE_LOOKUP(dns_transaction_source
, DnsTransactionSource
);