1 /* SPDX-License-Identifier: LGPL-2.1-or-later */
4 #include "sd-messages.h"
7 #include "alloc-util.h"
8 #include "dns-domain.h"
9 #include "errno-list.h"
10 #include "errno-util.h"
12 #include "glyph-util.h"
14 #include "random-util.h"
15 #include "resolved-dns-answer.h"
16 #include "resolved-dns-cache.h"
17 #include "resolved-dns-packet.h"
18 #include "resolved-dns-query.h"
19 #include "resolved-dns-question.h"
20 #include "resolved-dns-rr.h"
21 #include "resolved-dns-scope.h"
22 #include "resolved-dns-server.h"
23 #include "resolved-dns-stream.h"
24 #include "resolved-dns-transaction.h"
25 #include "resolved-dnstls.h"
26 #include "resolved-link.h"
27 #include "resolved-llmnr.h"
28 #include "resolved-manager.h"
29 #include "resolved-socket-graveyard.h"
30 #include "resolved-timeouts.h"
32 #include "string-table.h"
33 #include "string-util.h"
35 #define TRANSACTIONS_MAX 4096
37 static void dns_transaction_reset_answer(DnsTransaction
*t
) {
40 t
->received
= dns_packet_unref(t
->received
);
41 t
->answer
= dns_answer_unref(t
->answer
);
43 t
->answer_ede_rcode
= _DNS_EDE_RCODE_INVALID
;
44 t
->answer_ede_msg
= mfree(t
->answer_ede_msg
);
45 t
->answer_dnssec_result
= _DNSSEC_RESULT_INVALID
;
46 t
->answer_source
= _DNS_TRANSACTION_SOURCE_INVALID
;
47 t
->answer_query_flags
= 0;
48 t
->answer_nsec_ttl
= UINT32_MAX
;
52 static void dns_transaction_flush_dnssec_transactions(DnsTransaction
*t
) {
57 while ((z
= set_steal_first(t
->dnssec_transactions
))) {
58 set_remove(z
->notify_transactions
, t
);
59 set_remove(z
->notify_transactions_done
, t
);
60 dns_transaction_gc(z
);
64 static void dns_transaction_close_connection(
66 bool use_graveyard
) { /* Set use_graveyard = false when you know the connection is already
67 * dead, for example because you got a connection error back from the
68 * kernel. In that case there's no point in keeping the fd around,
75 /* Let's detach the stream from our transaction, in case something else keeps a reference to it. */
76 LIST_REMOVE(transactions_by_stream
, t
->stream
->transactions
, t
);
78 /* Remove packet in case it's still in the queue */
79 dns_packet_unref(ordered_set_remove(t
->stream
->write_queue
, t
->sent
));
81 t
->stream
= dns_stream_unref(t
->stream
);
84 t
->dns_udp_event_source
= sd_event_source_disable_unref(t
->dns_udp_event_source
);
86 /* If we have a UDP socket where we sent a packet, but never received one, then add it to the socket
87 * graveyard, instead of closing it right away. That way it will stick around for a moment longer,
88 * and the reply we might still get from the server will be eaten up instead of resulting in an ICMP
89 * port unreachable error message. */
91 /* Skip the graveyard stuff when we're shutting down, since that requires running event loop.
92 * Note that this is also called from dns_transaction_free(). In that case, scope may be NULL. */
95 !t
->scope
->manager
->event
||
96 sd_event_get_state(t
->scope
->manager
->event
) == SD_EVENT_FINISHED
)
97 use_graveyard
= false;
99 if (use_graveyard
&& t
->dns_udp_fd
>= 0 && t
->sent
&& !t
->received
) {
100 r
= manager_add_socket_to_graveyard(t
->scope
->manager
, t
->dns_udp_fd
);
102 log_debug_errno(r
, "Failed to add UDP socket to graveyard, closing immediately: %m");
104 TAKE_FD(t
->dns_udp_fd
);
107 t
->dns_udp_fd
= safe_close(t
->dns_udp_fd
);
110 static void dns_transaction_stop_timeout(DnsTransaction
*t
) {
113 t
->timeout_event_source
= sd_event_source_disable_unref(t
->timeout_event_source
);
116 DnsTransaction
* dns_transaction_free(DnsTransaction
*t
) {
117 DnsQueryCandidate
*c
;
124 log_debug("Freeing transaction %" PRIu16
".", t
->id
);
126 dns_transaction_close_connection(t
, true);
127 dns_transaction_stop_timeout(t
);
129 dns_packet_unref(t
->sent
);
130 dns_transaction_reset_answer(t
);
132 dns_server_unref(t
->server
);
136 DnsTransaction
*first
;
138 first
= hashmap_get(t
->scope
->transactions_by_key
, t
->key
);
139 LIST_REMOVE(transactions_by_key
, first
, t
);
141 hashmap_replace(t
->scope
->transactions_by_key
, first
->key
, first
);
143 hashmap_remove(t
->scope
->transactions_by_key
, t
->key
);
146 LIST_REMOVE(transactions_by_scope
, t
->scope
->transactions
, t
);
149 hashmap_remove(t
->scope
->manager
->dns_transactions
, UINT_TO_PTR(t
->id
));
152 while ((c
= set_steal_first(t
->notify_query_candidates
)))
153 set_remove(c
->transactions
, t
);
154 set_free(t
->notify_query_candidates
);
156 while ((c
= set_steal_first(t
->notify_query_candidates_done
)))
157 set_remove(c
->transactions
, t
);
158 set_free(t
->notify_query_candidates_done
);
160 while ((i
= set_steal_first(t
->notify_zone_items
)))
161 i
->probe_transaction
= NULL
;
162 set_free(t
->notify_zone_items
);
164 while ((i
= set_steal_first(t
->notify_zone_items_done
)))
165 i
->probe_transaction
= NULL
;
166 set_free(t
->notify_zone_items_done
);
168 while ((z
= set_steal_first(t
->notify_transactions
)))
169 set_remove(z
->dnssec_transactions
, t
);
170 set_free(t
->notify_transactions
);
172 while ((z
= set_steal_first(t
->notify_transactions_done
)))
173 set_remove(z
->dnssec_transactions
, t
);
174 set_free(t
->notify_transactions_done
);
176 dns_transaction_flush_dnssec_transactions(t
);
177 set_free(t
->dnssec_transactions
);
179 dns_answer_unref(t
->validated_keys
);
180 dns_resource_key_unref(t
->key
);
181 dns_packet_unref(t
->bypass
);
186 DEFINE_TRIVIAL_CLEANUP_FUNC(DnsTransaction
*, dns_transaction_free
);
188 DnsTransaction
* dns_transaction_gc(DnsTransaction
*t
) {
191 /* Returns !NULL if we can't gc yet. */
196 if (t
->wait_for_answer
&& IN_SET(t
->state
, DNS_TRANSACTION_PENDING
, DNS_TRANSACTION_VALIDATING
))
199 if (set_isempty(t
->notify_query_candidates
) &&
200 set_isempty(t
->notify_query_candidates_done
) &&
201 set_isempty(t
->notify_zone_items
) &&
202 set_isempty(t
->notify_zone_items_done
) &&
203 set_isempty(t
->notify_transactions
) &&
204 set_isempty(t
->notify_transactions_done
))
205 return dns_transaction_free(t
);
210 static uint16_t pick_new_id(Manager
*m
) {
213 /* Find a fresh, unused transaction id. Note that this loop is bounded because there's a limit on the
214 * number of transactions, and it's much lower than the space of IDs. */
216 assert_cc(TRANSACTIONS_MAX
< 0xFFFF);
219 random_bytes(&new_id
, sizeof(new_id
));
220 while (new_id
== 0 ||
221 hashmap_get(m
->dns_transactions
, UINT_TO_PTR(new_id
)));
228 DnsResourceKey
*key
) {
230 /* Don't allow looking up invalid or pseudo RRs */
231 if (!dns_type_is_valid_query(key
->type
))
233 if (dns_type_is_obsolete(key
->type
))
236 /* We only support the IN class */
237 if (!IN_SET(key
->class, DNS_CLASS_IN
, DNS_CLASS_ANY
))
240 /* Don't allows DNSSEC RRs to be looked up via LLMNR/mDNS. They don't really make sense
241 * there, and it speeds up our queries if we refuse this early */
242 if (scope
->protocol
!= DNS_PROTOCOL_DNS
&&
243 dns_type_is_dnssec(key
->type
))
249 int dns_transaction_new(
250 DnsTransaction
**ret
,
254 uint64_t query_flags
) {
256 _cleanup_(dns_transaction_freep
) DnsTransaction
*t
= NULL
;
272 r
= dns_packet_validate_query(bypass
);
276 DNS_QUESTION_FOREACH(qk
, bypass
->question
) {
283 if (hashmap_size(s
->manager
->dns_transactions
) >= TRANSACTIONS_MAX
)
286 r
= hashmap_ensure_allocated(&s
->manager
->dns_transactions
, NULL
);
291 r
= hashmap_ensure_allocated(&s
->transactions_by_key
, &dns_resource_key_hash_ops
);
296 t
= new(DnsTransaction
, 1);
300 *t
= (DnsTransaction
) {
301 .dns_udp_fd
= -EBADF
,
302 .answer_source
= _DNS_TRANSACTION_SOURCE_INVALID
,
303 .answer_dnssec_result
= _DNSSEC_RESULT_INVALID
,
304 .answer_ede_rcode
= _DNS_EDE_RCODE_INVALID
,
305 .answer_nsec_ttl
= UINT32_MAX
,
306 .key
= dns_resource_key_ref(key
),
307 .query_flags
= query_flags
,
308 .bypass
= dns_packet_ref(bypass
),
309 .current_feature_level
= _DNS_SERVER_FEATURE_LEVEL_INVALID
,
310 .clamp_feature_level_servfail
= _DNS_SERVER_FEATURE_LEVEL_INVALID
,
311 .id
= pick_new_id(s
->manager
),
314 r
= hashmap_put(s
->manager
->dns_transactions
, UINT_TO_PTR(t
->id
), t
);
321 DnsTransaction
*first
;
323 first
= hashmap_get(s
->transactions_by_key
, t
->key
);
324 LIST_PREPEND(transactions_by_key
, first
, t
);
326 r
= hashmap_replace(s
->transactions_by_key
, first
->key
, first
);
328 LIST_REMOVE(transactions_by_key
, first
, t
);
333 LIST_PREPEND(transactions_by_scope
, s
->transactions
, t
);
336 s
->manager
->n_transactions_total
++;
345 static void dns_transaction_shuffle_id(DnsTransaction
*t
) {
349 /* Pick a new ID for this transaction. */
351 new_id
= pick_new_id(t
->scope
->manager
);
352 assert_se(hashmap_remove_and_put(t
->scope
->manager
->dns_transactions
, UINT_TO_PTR(t
->id
), UINT_TO_PTR(new_id
), t
) >= 0);
354 log_debug("Transaction %" PRIu16
" is now %" PRIu16
".", t
->id
, new_id
);
357 /* Make sure we generate a new packet with the new ID */
358 t
->sent
= dns_packet_unref(t
->sent
);
361 static void dns_transaction_tentative(DnsTransaction
*t
, DnsPacket
*p
) {
362 char key_str
[DNS_RESOURCE_KEY_STRING_MAX
];
367 assert(t
->scope
->protocol
== DNS_PROTOCOL_LLMNR
);
369 if (manager_packet_from_local_address(t
->scope
->manager
, p
) != 0)
372 log_debug("Transaction %" PRIu16
" for <%s> on scope %s on %s/%s got tentative packet from %s.",
374 dns_resource_key_to_string(dns_transaction_key(t
), key_str
, sizeof key_str
),
375 dns_protocol_to_string(t
->scope
->protocol
),
376 t
->scope
->link
? t
->scope
->link
->ifname
: "*",
377 af_to_name_short(t
->scope
->family
),
378 IN_ADDR_TO_STRING(p
->family
, &p
->sender
));
380 /* RFC 4795, Section 4.1 says that the peer with the
381 * lexicographically smaller IP address loses */
382 if (memcmp(&p
->sender
, &p
->destination
, FAMILY_ADDRESS_SIZE(p
->family
)) >= 0) {
383 log_debug("Peer has lexicographically larger IP address and thus lost in the conflict.");
387 log_debug("We have the lexicographically larger IP address and thus lost in the conflict.");
391 while ((z
= set_first(t
->notify_zone_items
))) {
392 /* First, make sure the zone item drops the reference
394 dns_zone_item_probe_stop(z
);
396 /* Secondly, report this as conflict, so that we might
397 * look for a different hostname */
398 dns_zone_item_conflict(z
);
402 dns_transaction_gc(t
);
405 void dns_transaction_complete(DnsTransaction
*t
, DnsTransactionState state
) {
406 DnsQueryCandidate
*c
;
410 char key_str
[DNS_RESOURCE_KEY_STRING_MAX
];
413 assert(!DNS_TRANSACTION_IS_LIVE(state
));
415 if (state
== DNS_TRANSACTION_DNSSEC_FAILED
) {
416 dns_resource_key_to_string(dns_transaction_key(t
), key_str
, sizeof key_str
);
418 log_struct(LOG_NOTICE
,
419 LOG_MESSAGE_ID(SD_MESSAGE_DNSSEC_FAILURE_STR
),
420 LOG_MESSAGE("DNSSEC validation failed for question %s: %s",
421 key_str
, dnssec_result_to_string(t
->answer_dnssec_result
)),
422 LOG_ITEM("DNS_TRANSACTION=%" PRIu16
, t
->id
),
423 LOG_ITEM("DNS_QUESTION=%s", key_str
),
424 LOG_ITEM("DNSSEC_RESULT=%s", dnssec_result_to_string(t
->answer_dnssec_result
)),
425 LOG_ITEM("DNS_SERVER=%s", strna(dns_server_string_full(t
->server
))),
426 LOG_ITEM("DNS_SERVER_FEATURE_LEVEL=%s", dns_server_feature_level_to_string(t
->server
->possible_feature_level
)));
429 /* Note that this call might invalidate the query. Callers
430 * should hence not attempt to access the query or transaction
431 * after calling this function. */
433 if (state
== DNS_TRANSACTION_ERRNO
)
434 st
= errno_to_name(t
->answer_errno
);
436 st
= dns_transaction_state_to_string(state
);
438 log_debug("%s transaction %" PRIu16
" for <%s> on scope %s on %s/%s now complete with <%s> from %s (%s; %s).",
439 t
->bypass
? "Bypass" : "Regular",
441 dns_resource_key_to_string(dns_transaction_key(t
), key_str
, sizeof key_str
),
442 dns_protocol_to_string(t
->scope
->protocol
),
443 t
->scope
->link
? t
->scope
->link
->ifname
: "*",
444 af_to_name_short(t
->scope
->family
),
446 t
->answer_source
< 0 ? "none" : dns_transaction_source_to_string(t
->answer_source
),
447 FLAGS_SET(t
->query_flags
, SD_RESOLVED_NO_VALIDATE
) ? "not validated" :
448 (FLAGS_SET(t
->answer_query_flags
, SD_RESOLVED_AUTHENTICATED
) ? "authenticated" : "unsigned"),
449 FLAGS_SET(t
->answer_query_flags
, SD_RESOLVED_CONFIDENTIAL
) ? "confidential" : "non-confidential");
453 dns_transaction_close_connection(t
, true);
454 dns_transaction_stop_timeout(t
);
456 /* Notify all queries that are interested, but make sure the
457 * transaction isn't freed while we are still looking at it */
460 SET_FOREACH_MOVE(c
, t
->notify_query_candidates_done
, t
->notify_query_candidates
)
461 dns_query_candidate_notify(c
);
462 SWAP_TWO(t
->notify_query_candidates
, t
->notify_query_candidates_done
);
464 SET_FOREACH_MOVE(z
, t
->notify_zone_items_done
, t
->notify_zone_items
)
465 dns_zone_item_notify(z
);
466 SWAP_TWO(t
->notify_zone_items
, t
->notify_zone_items_done
);
467 if (t
->probing
&& t
->state
== DNS_TRANSACTION_ATTEMPTS_MAX_REACHED
)
468 (void) dns_scope_announce(t
->scope
, false);
470 SET_FOREACH_MOVE(d
, t
->notify_transactions_done
, t
->notify_transactions
)
471 dns_transaction_notify(d
, t
);
472 SWAP_TWO(t
->notify_transactions
, t
->notify_transactions_done
);
475 dns_transaction_gc(t
);
478 static void dns_transaction_complete_errno(DnsTransaction
*t
, int error
) {
482 t
->answer_errno
= ABS(error
);
483 dns_transaction_complete(t
, DNS_TRANSACTION_ERRNO
);
486 static int dns_transaction_pick_server(DnsTransaction
*t
) {
490 assert(t
->scope
->protocol
== DNS_PROTOCOL_DNS
);
492 /* Pick a DNS server and a feature level for it. */
494 server
= dns_scope_get_dns_server(t
->scope
);
498 /* If we changed the server invalidate the feature level clamping, as the new server might have completely
499 * different properties. */
500 if (server
!= t
->server
)
501 t
->clamp_feature_level_servfail
= _DNS_SERVER_FEATURE_LEVEL_INVALID
;
503 t
->current_feature_level
= dns_server_possible_feature_level(server
);
505 /* Clamp the feature level if that is requested. */
506 if (t
->clamp_feature_level_servfail
!= _DNS_SERVER_FEATURE_LEVEL_INVALID
&&
507 t
->current_feature_level
> t
->clamp_feature_level_servfail
)
508 t
->current_feature_level
= t
->clamp_feature_level_servfail
;
510 log_debug("Using feature level %s for transaction %u.", dns_server_feature_level_to_string(t
->current_feature_level
), t
->id
);
512 if (server
== t
->server
)
515 dns_server_unref(t
->server
);
516 t
->server
= dns_server_ref(server
);
518 t
->n_picked_servers
++;
520 log_debug("Using DNS server %s for transaction %u.", strna(dns_server_string_full(t
->server
)), t
->id
);
525 static void dns_transaction_retry(DnsTransaction
*t
, bool next_server
) {
530 /* Retries the transaction as it is, possibly on a different server */
532 if (next_server
&& t
->scope
->protocol
== DNS_PROTOCOL_DNS
)
533 log_debug("Retrying transaction %" PRIu16
", after switching servers.", t
->id
);
535 log_debug("Retrying transaction %" PRIu16
".", t
->id
);
537 /* Before we try again, switch to a new server. */
539 dns_scope_next_dns_server(t
->scope
, t
->server
);
541 r
= dns_transaction_go(t
);
543 dns_transaction_complete_errno(t
, r
);
546 static bool dns_transaction_limited_retry(DnsTransaction
*t
) {
549 /* If we haven't tried all different servers yet, let's try again with a different server */
551 if (t
->n_picked_servers
>= dns_scope_get_n_dns_servers(t
->scope
))
554 dns_transaction_retry(t
, /* next_server= */ true);
558 static int dns_transaction_maybe_restart(DnsTransaction
*t
) {
563 /* Restarts the transaction, under a new ID if the feature level of the server changed since we first
564 * tried, without changing DNS server. Returns > 0 if the transaction was restarted, 0 if not. */
569 if (t
->current_feature_level
<= dns_server_possible_feature_level(t
->server
))
572 /* The server's current feature level is lower than when we sent the original query. We learnt something from
573 the response or possibly an auxiliary DNSSEC response that we didn't know before. We take that as reason to
574 restart the whole transaction. This is a good idea to deal with servers that respond rubbish if we include
575 OPT RR or DO bit. One of these cases is documented here, for example:
576 https://open.nlnetlabs.nl/pipermail/dnssec-trigger/2014-November/000376.html */
578 log_debug("Server feature level is now lower than when we began our transaction. Restarting with new ID.");
579 dns_transaction_shuffle_id(t
);
581 r
= dns_transaction_go(t
);
588 static void on_transaction_stream_error(DnsTransaction
*t
, int error
) {
591 dns_transaction_close_connection(t
, true);
593 if (ERRNO_IS_DISCONNECT(error
)) {
594 if (t
->scope
->protocol
== DNS_PROTOCOL_LLMNR
) {
595 /* If the LLMNR/TCP connection failed, the host doesn't support LLMNR, and we cannot answer the
596 * question on this scope. */
597 dns_transaction_complete(t
, DNS_TRANSACTION_NOT_FOUND
);
601 dns_transaction_retry(t
, true);
605 dns_transaction_complete_errno(t
, error
);
608 static int dns_transaction_on_stream_packet(DnsTransaction
*t
, DnsStream
*s
, DnsPacket
*p
) {
615 encrypted
= s
->encrypted
;
617 dns_transaction_close_connection(t
, true);
619 if (dns_packet_validate_reply(p
) <= 0) {
620 log_debug("Invalid TCP reply packet.");
621 dns_transaction_complete(t
, DNS_TRANSACTION_INVALID_REPLY
);
625 dns_scope_check_conflicts(t
->scope
, p
);
628 dns_transaction_process_reply(t
, p
, encrypted
);
631 /* If the response wasn't useful, then complete the transition
632 * now. After all, we are the worst feature set now with TCP
633 * sockets, and there's really no point in retrying. */
634 if (t
->state
== DNS_TRANSACTION_PENDING
)
635 dns_transaction_complete(t
, DNS_TRANSACTION_INVALID_REPLY
);
637 dns_transaction_gc(t
);
642 static int on_stream_complete(DnsStream
*s
, int error
) {
645 if (ERRNO_IS_DISCONNECT(error
) && s
->protocol
!= DNS_PROTOCOL_LLMNR
) {
646 log_debug_errno(error
, "Connection failure for DNS TCP stream: %m");
648 if (error
!= ECONNRESET
&& s
->transactions
) {
652 dns_server_packet_lost(t
->server
, IPPROTO_TCP
, t
->current_feature_level
);
657 /* First, detach the stream from the server. Otherwise, transactions attached to this stream
658 * may be restarted by on_transaction_stream_error() below with this stream. */
659 dns_stream_detach(s
);
661 /* Do not use LIST_FOREACH() here, as
662 * on_transaction_stream_error()
663 * -> dns_transaction_complete_errno()
664 * -> dns_transaction_free()
665 * may free multiple transactions in the list. */
667 while ((t
= s
->transactions
))
668 on_transaction_stream_error(t
, error
);
674 static int on_stream_packet(DnsStream
*s
, DnsPacket
*p
) {
681 t
= hashmap_get(s
->manager
->dns_transactions
, UINT_TO_PTR(DNS_PACKET_ID(p
)));
682 if (t
&& t
->stream
== s
) /* Validate that the stream we got this on actually is the stream the
683 * transaction was using. */
684 return dns_transaction_on_stream_packet(t
, s
, p
);
686 /* Ignore incorrect transaction id as an old transaction can have been canceled. */
687 log_debug("Received unexpected TCP reply packet with id %" PRIu16
", ignoring.", DNS_PACKET_ID(p
));
691 static uint16_t dns_transaction_port(DnsTransaction
*t
) {
694 if (t
->server
->port
> 0)
695 return t
->server
->port
;
697 return DNS_SERVER_FEATURE_LEVEL_IS_TLS(t
->current_feature_level
) ? 853 : 53;
700 static int dns_transaction_emit_tcp(DnsTransaction
*t
) {
701 usec_t stream_timeout_usec
= DNS_STREAM_DEFAULT_TIMEOUT_USEC
;
702 _cleanup_(dns_stream_unrefp
) DnsStream
*s
= NULL
;
703 _cleanup_close_
int fd
= -EBADF
;
704 union sockaddr_union sa
;
711 dns_transaction_close_connection(t
, true);
713 switch (t
->scope
->protocol
) {
715 case DNS_PROTOCOL_DNS
:
716 r
= dns_transaction_pick_server(t
);
720 if (manager_server_is_stub(t
->scope
->manager
, t
->server
))
724 if (!dns_server_dnssec_supported(t
->server
) && dns_type_is_dnssec(dns_transaction_key(t
)->type
))
727 r
= dns_server_adjust_opt(t
->server
, t
->sent
, t
->current_feature_level
);
732 if (t
->server
->stream
&& (DNS_SERVER_FEATURE_LEVEL_IS_TLS(t
->current_feature_level
) == t
->server
->stream
->encrypted
))
733 s
= dns_stream_ref(t
->server
->stream
);
735 fd
= dns_scope_socket_tcp(t
->scope
, AF_UNSPEC
, NULL
, t
->server
, dns_transaction_port(t
), &sa
);
737 /* Lower timeout in DNS-over-TLS opportunistic mode. In environments where DoT is blocked
738 * without ICMP response overly long delays when contacting DoT servers are nasty, in
739 * particular if multiple DNS servers are defined which we try in turn and all are
740 * blocked. Hence, substantially lower the timeout in that case. */
741 if (DNS_SERVER_FEATURE_LEVEL_IS_TLS(t
->current_feature_level
) &&
742 dns_server_get_dns_over_tls_mode(t
->server
) == DNS_OVER_TLS_OPPORTUNISTIC
)
743 stream_timeout_usec
= DNS_STREAM_OPPORTUNISTIC_TLS_TIMEOUT_USEC
;
745 type
= DNS_STREAM_LOOKUP
;
748 case DNS_PROTOCOL_LLMNR
:
749 /* When we already received a reply to this (but it was truncated), send to its sender address */
751 fd
= dns_scope_socket_tcp(t
->scope
, t
->received
->family
, &t
->received
->sender
, NULL
, t
->received
->sender_port
, &sa
);
753 union in_addr_union address
;
754 int family
= AF_UNSPEC
;
756 /* Otherwise, try to talk to the owner of a
757 * the IP address, in case this is a reverse
760 r
= dns_name_address(dns_resource_key_name(dns_transaction_key(t
)), &family
, &address
);
765 if (family
!= t
->scope
->family
)
768 fd
= dns_scope_socket_tcp(t
->scope
, family
, &address
, NULL
, LLMNR_PORT
, &sa
);
771 type
= DNS_STREAM_LLMNR_SEND
;
775 return -EAFNOSUPPORT
;
782 r
= dns_stream_new(t
->scope
->manager
, &s
, type
, t
->scope
->protocol
, fd
, &sa
,
783 on_stream_packet
, on_stream_complete
, stream_timeout_usec
);
789 #if ENABLE_DNS_OVER_TLS
790 if (t
->scope
->protocol
== DNS_PROTOCOL_DNS
&&
791 DNS_SERVER_FEATURE_LEVEL_IS_TLS(t
->current_feature_level
)) {
794 r
= dnstls_stream_connect_tls(s
, t
->server
);
801 dns_server_unref_stream(t
->server
);
802 s
->server
= dns_server_ref(t
->server
);
803 t
->server
->stream
= dns_stream_ref(s
);
806 /* The interface index is difficult to determine if we are
807 * connecting to the local host, hence fill this in right away
808 * instead of determining it from the socket */
809 s
->ifindex
= dns_scope_ifindex(t
->scope
);
812 t
->stream
= TAKE_PTR(s
);
813 LIST_PREPEND(transactions_by_stream
, t
->stream
->transactions
, t
);
815 r
= dns_stream_write_packet(t
->stream
, t
->sent
);
817 dns_transaction_close_connection(t
, /* use_graveyard= */ false);
821 dns_transaction_reset_answer(t
);
823 t
->tried_stream
= true;
828 static void dns_transaction_cache_answer(DnsTransaction
*t
) {
831 /* For mDNS we cache whenever we get the packet, rather than
832 * in each transaction. */
833 if (!IN_SET(t
->scope
->protocol
, DNS_PROTOCOL_DNS
, DNS_PROTOCOL_LLMNR
))
836 /* Caching disabled? */
837 if (t
->scope
->manager
->enable_cache
== DNS_CACHE_MODE_NO
)
840 /* If validation is turned off for this transaction, but DNSSEC is on, then let's not cache this */
841 if (FLAGS_SET(t
->query_flags
, SD_RESOLVED_NO_VALIDATE
) && t
->scope
->dnssec_mode
!= DNSSEC_NO
)
844 /* Packet from localhost? */
845 if (!t
->scope
->manager
->cache_from_localhost
&&
846 in_addr_is_localhost(t
->received
->family
, &t
->received
->sender
) != 0)
849 dns_cache_put(&t
->scope
->cache
,
850 t
->scope
->manager
->enable_cache
,
852 dns_transaction_key(t
),
855 /* If neither DO nor EDE is set, the full packet isn't useful to cache */
856 dns_packet_do(t
->received
) || t
->answer_ede_rcode
> 0 || t
->answer_ede_msg
? t
->received
: NULL
,
857 t
->answer_query_flags
,
858 t
->answer_dnssec_result
,
861 &t
->received
->sender
,
862 t
->scope
->manager
->stale_retention_usec
);
865 static bool dns_transaction_dnssec_is_live(DnsTransaction
*t
) {
870 SET_FOREACH(dt
, t
->dnssec_transactions
)
871 if (DNS_TRANSACTION_IS_LIVE(dt
->state
))
877 static int dns_transaction_dnssec_ready(DnsTransaction
*t
) {
883 /* Checks whether the auxiliary DNSSEC transactions of our transaction have completed, or are still
884 * ongoing. Returns 0, if we aren't ready for the DNSSEC validation, positive if we are. */
886 SET_FOREACH(dt
, t
->dnssec_transactions
) {
890 case DNS_TRANSACTION_NULL
:
891 case DNS_TRANSACTION_PENDING
:
892 case DNS_TRANSACTION_VALIDATING
:
896 case DNS_TRANSACTION_RCODE_FAILURE
:
897 if (!IN_SET(dt
->answer_rcode
, DNS_RCODE_NXDOMAIN
, DNS_RCODE_SERVFAIL
)) {
898 log_debug("Auxiliary DNSSEC RR query failed with rcode=%s.", FORMAT_DNS_RCODE(dt
->answer_rcode
));
902 /* Fall-through: NXDOMAIN/SERVFAIL is good enough for us. This is because some DNS servers
903 * erroneously return NXDOMAIN/SERVFAIL for empty non-terminals (Akamai...) or missing DS
904 * records (Facebook), and we need to handle that nicely, when asking for parent SOA or similar
905 * RRs to make unsigned proofs. */
907 case DNS_TRANSACTION_SUCCESS
:
911 case DNS_TRANSACTION_DNSSEC_FAILED
:
912 /* We handle DNSSEC failures different from other errors, as we care about the DNSSEC
913 * validation result */
915 log_debug("Auxiliary DNSSEC RR query failed validation: %s%s%s%s%s%s",
916 dnssec_result_to_string(dt
->answer_dnssec_result
),
917 dt
->answer_ede_rcode
>= 0 ? " (" : "",
918 dt
->answer_ede_rcode
>= 0 ? FORMAT_DNS_EDE_RCODE(dt
->answer_ede_rcode
) : "",
919 (dt
->answer_ede_rcode
>= 0 && !isempty(dt
->answer_ede_msg
)) ? ": " : "",
920 dt
->answer_ede_rcode
>= 0 ? strempty(dt
->answer_ede_msg
) : "",
921 dt
->answer_ede_rcode
>= 0 ? ")" : "");
923 /* Copy error code over */
924 t
->answer_dnssec_result
= dt
->answer_dnssec_result
;
925 t
->answer_ede_rcode
= dt
->answer_ede_rcode
;
926 r
= free_and_strdup(&t
->answer_ede_msg
, dt
->answer_ede_msg
);
930 /* The answer would normally be replaced by the validated subset, but at this point
931 * we aren't going to bother validating the rest, so just drop it. */
932 t
->answer
= dns_answer_unref(t
->answer
);
934 dns_transaction_complete(t
, DNS_TRANSACTION_DNSSEC_FAILED
);
938 log_debug("Auxiliary DNSSEC RR query failed with %s", dns_transaction_state_to_string(dt
->state
));
943 /* All is ready, we can go and validate */
947 /* Some auxiliary DNSSEC transaction failed for some reason. Maybe we learned something about the
948 * server due to this failure, and the feature level is now different? Let's see and restart the
949 * transaction if so. If not, let's propagate the auxiliary failure.
951 * This is particularly relevant if an auxiliary request figured out that DNSSEC doesn't work, and we
952 * are in permissive DNSSEC mode, and thus should restart things without DNSSEC magic. */
953 r
= dns_transaction_maybe_restart(t
);
957 return 0; /* don't validate just yet, we restarted things */
959 t
->answer_dnssec_result
= DNSSEC_FAILED_AUXILIARY
;
960 dns_transaction_complete(t
, DNS_TRANSACTION_DNSSEC_FAILED
);
964 static void dns_transaction_process_dnssec(DnsTransaction
*t
) {
969 /* Are there ongoing DNSSEC transactions? If so, let's wait for them. */
970 r
= dns_transaction_dnssec_ready(t
);
973 if (r
== 0) /* We aren't ready yet (or one of our auxiliary transactions failed, and we shouldn't validate now */
976 /* See if we learnt things from the additional DNSSEC transactions, that we didn't know before, and better
977 * restart the lookup immediately. */
978 r
= dns_transaction_maybe_restart(t
);
981 if (r
> 0) /* Transaction got restarted... */
984 /* All our auxiliary DNSSEC transactions are complete now. Try
985 * to validate our RRset now. */
986 r
= dns_transaction_validate_dnssec(t
);
988 dns_transaction_complete(t
, DNS_TRANSACTION_INVALID_REPLY
);
994 if (t
->answer_dnssec_result
== DNSSEC_INCOMPATIBLE_SERVER
&&
995 t
->scope
->dnssec_mode
== DNSSEC_YES
) {
997 /* We are not in automatic downgrade mode, and the server is bad. Let's try a different server, maybe
1000 if (dns_transaction_limited_retry(t
))
1003 /* OK, let's give up, apparently all servers we tried didn't work. */
1004 dns_transaction_complete(t
, DNS_TRANSACTION_DNSSEC_FAILED
);
1008 if (!IN_SET(t
->answer_dnssec_result
,
1009 _DNSSEC_RESULT_INVALID
, /* No DNSSEC validation enabled */
1010 DNSSEC_VALIDATED
, /* Answer is signed and validated successfully */
1011 DNSSEC_UNSIGNED
, /* Answer is right-fully unsigned */
1012 DNSSEC_INCOMPATIBLE_SERVER
)) { /* Server does not do DNSSEC (Yay, we are downgrade attack vulnerable!) */
1013 dns_transaction_complete(t
, DNS_TRANSACTION_DNSSEC_FAILED
);
1017 if (t
->answer_dnssec_result
== DNSSEC_INCOMPATIBLE_SERVER
)
1018 dns_server_warn_downgrade(t
->server
);
1020 dns_transaction_cache_answer(t
);
1022 if (t
->answer_rcode
== DNS_RCODE_SUCCESS
)
1023 dns_transaction_complete(t
, DNS_TRANSACTION_SUCCESS
);
1025 dns_transaction_complete(t
, DNS_TRANSACTION_RCODE_FAILURE
);
1030 dns_transaction_complete_errno(t
, r
);
1033 static int dns_transaction_has_positive_answer(DnsTransaction
*t
, DnsAnswerFlags
*flags
) {
1038 /* Checks whether the answer is positive, i.e. either a direct
1039 * answer to the question, or a CNAME/DNAME for it */
1041 r
= dns_answer_match_key(t
->answer
, dns_transaction_key(t
), flags
);
1045 r
= dns_answer_find_cname_or_dname(t
->answer
, dns_transaction_key(t
), NULL
, flags
);
1052 static int dns_transaction_fix_rcode(DnsTransaction
*t
) {
1057 /* Fix up the RCODE to SUCCESS if we get at least one matching RR in a response. Note that this contradicts the
1058 * DNS RFCs a bit. Specifically, RFC 6604 Section 3 clarifies that the RCODE shall say something about a
1059 * CNAME/DNAME chain element coming after the last chain element contained in the message, and not the first
1060 * one included. However, it also indicates that not all DNS servers implement this correctly. Moreover, when
1061 * using DNSSEC we usually only can prove the first element of a CNAME/DNAME chain anyway, hence let's settle
1062 * on always processing the RCODE as referring to the immediate look-up we do, i.e. the first element of a
1063 * CNAME/DNAME chain. This way, we uniformly handle CNAME/DNAME chains, regardless if the DNS server
1064 * incorrectly implements RCODE, whether DNSSEC is in use, or whether the DNS server only supplied us with an
1065 * incomplete CNAME/DNAME chain.
1067 * Or in other words: if we get at least one positive reply in a message we patch NXDOMAIN to become SUCCESS,
1068 * and then rely on the CNAME chasing logic to figure out that there's actually a CNAME error with a new
1071 if (t
->answer_rcode
!= DNS_RCODE_NXDOMAIN
)
1074 r
= dns_transaction_has_positive_answer(t
, NULL
);
1078 t
->answer_rcode
= DNS_RCODE_SUCCESS
;
1082 void dns_transaction_process_reply(DnsTransaction
*t
, DnsPacket
*p
, bool encrypted
) {
1083 bool retry_with_tcp
= false;
1089 assert(t
->scope
->manager
);
1091 if (t
->state
!= DNS_TRANSACTION_PENDING
)
1094 /* Increment the total failure counter only when it is the first attempt at querying and the upstream
1095 * server returns a failure response code. This ensures a more accurate count of the number of queries
1096 * that received a failure response code, as it doesn't consider retries. */
1098 if (t
->n_attempts
== 1 && !IN_SET(dns_packet_rcode(p
), DNS_RCODE_SUCCESS
, DNS_RCODE_NXDOMAIN
))
1099 t
->scope
->manager
->n_failure_responses_total
++;
1101 /* Note that this call might invalidate the query. Callers
1102 * should hence not attempt to access the query or transaction
1103 * after calling this function. */
1105 log_debug("Processing incoming packet of size %zu on transaction %" PRIu16
" (rcode=%s).",
1107 t
->id
, FORMAT_DNS_RCODE(dns_packet_rcode(p
)));
1109 switch (t
->scope
->protocol
) {
1111 case DNS_PROTOCOL_LLMNR
:
1112 /* For LLMNR we will not accept any packets from other interfaces */
1114 if (p
->ifindex
!= dns_scope_ifindex(t
->scope
))
1117 if (p
->family
!= t
->scope
->family
)
1120 /* Tentative packets are not full responses but still
1121 * useful for identifying uniqueness conflicts during
1123 if (DNS_PACKET_LLMNR_T(p
)) {
1124 dns_transaction_tentative(t
, p
);
1130 case DNS_PROTOCOL_MDNS
:
1131 /* For mDNS we will not accept any packets from other interfaces */
1133 if (p
->ifindex
!= dns_scope_ifindex(t
->scope
))
1136 if (p
->family
!= t
->scope
->family
)
1141 case DNS_PROTOCOL_DNS
:
1142 /* Note that we do not need to verify the
1143 * addresses/port numbers of incoming traffic, as we
1144 * invoked connect() on our UDP socket in which case
1145 * the kernel already does the needed verification for
1150 assert_not_reached();
1153 if (t
->received
!= p
)
1154 DNS_PACKET_REPLACE(t
->received
, dns_packet_ref(p
));
1156 t
->answer_source
= DNS_TRANSACTION_NETWORK
;
1158 if (p
->ipproto
== IPPROTO_TCP
) {
1159 if (DNS_PACKET_TC(p
)) {
1160 /* Truncated via TCP? Somebody must be fucking with us */
1161 dns_transaction_complete(t
, DNS_TRANSACTION_INVALID_REPLY
);
1165 if (DNS_PACKET_ID(p
) != t
->id
) {
1166 /* Not the reply to our query? Somebody must be fucking with us */
1167 dns_transaction_complete(t
, DNS_TRANSACTION_INVALID_REPLY
);
1172 if (DNS_PACKET_TC(p
)) {
1174 /* Truncated packets for mDNS are not allowed. Give up immediately. */
1175 if (t
->scope
->protocol
== DNS_PROTOCOL_MDNS
) {
1176 dns_transaction_complete(t
, DNS_TRANSACTION_INVALID_REPLY
);
1180 /* Response was truncated, let's try again with good old TCP */
1181 log_debug("Reply truncated, retrying via TCP.");
1182 retry_with_tcp
= true;
1184 } else if (t
->scope
->protocol
== DNS_PROTOCOL_DNS
&&
1185 DNS_PACKET_IS_FRAGMENTED(p
)) {
1187 /* Report the fragment size, so that we downgrade from LARGE to regular EDNS0 if needed */
1189 dns_server_packet_udp_fragmented(t
->server
, dns_packet_size_unfragmented(p
));
1191 if (t
->current_feature_level
> DNS_SERVER_FEATURE_LEVEL_UDP
) {
1192 /* Packet was fragmented. Let's retry with TCP to avoid fragmentation attack
1193 * issues. (We don't do that on the lowest feature level however, since crappy DNS
1194 * servers often do not implement TCP, hence falling back to TCP on fragmentation is
1195 * counter-productive there.) */
1197 log_debug("Reply fragmented, retrying via TCP. (Largest fragment size: %zu; Datagram size: %zu)",
1198 p
->fragsize
, p
->size
);
1199 retry_with_tcp
= true;
1203 if (retry_with_tcp
) {
1204 r
= dns_transaction_emit_tcp(t
);
1206 /* No servers found? Damn! */
1207 dns_transaction_complete(t
, DNS_TRANSACTION_NO_SERVERS
);
1210 if (r
== -EOPNOTSUPP
) {
1211 /* Tried to ask for DNSSEC RRs, on a server that doesn't do DNSSEC */
1212 dns_transaction_complete(t
, DNS_TRANSACTION_RR_TYPE_UNSUPPORTED
);
1216 /* On LLMNR, if we cannot connect to the host,
1217 * we immediately give up */
1218 if (t
->scope
->protocol
!= DNS_PROTOCOL_DNS
)
1221 /* On DNS, couldn't send? Try immediately again, with a new server */
1222 if (dns_transaction_limited_retry(t
))
1225 /* No new server to try, give up */
1226 dns_transaction_complete(t
, DNS_TRANSACTION_ATTEMPTS_MAX_REACHED
);
1232 /* After the superficial checks, actually parse the message. */
1233 r
= dns_packet_extract(p
);
1236 dns_server_packet_invalid(t
->server
, t
->current_feature_level
);
1238 r
= dns_transaction_maybe_restart(t
);
1241 if (r
> 0) /* Transaction got restarted... */
1245 dns_transaction_complete(t
, DNS_TRANSACTION_INVALID_REPLY
);
1249 switch (t
->scope
->protocol
) {
1251 case DNS_PROTOCOL_DNS
: {
1254 (void) dns_packet_ede_rcode(p
, &t
->answer_ede_rcode
, &t
->answer_ede_msg
);
1257 IN_SET(dns_packet_rcode(p
), DNS_RCODE_FORMERR
, DNS_RCODE_SERVFAIL
, DNS_RCODE_NOTIMP
)) {
1258 /* If the server has replied with detailed error data, using a degraded feature set
1259 * will likely not help anyone. Examine the detailed error to determine the best
1260 * course of action. */
1261 if (t
->answer_ede_rcode
>= 0 && dns_packet_rcode(p
) == DNS_RCODE_SERVFAIL
) {
1262 /* These codes are related to DNSSEC configuration errors. If accurate,
1263 * this is the domain operator's problem, and retrying won't help. */
1264 if (dns_ede_rcode_is_dnssec(t
->answer_ede_rcode
)) {
1265 log_debug("Server returned error: %s (%s%s%s). Lookup failed.",
1266 FORMAT_DNS_RCODE(dns_packet_rcode(p
)),
1267 FORMAT_DNS_EDE_RCODE(t
->answer_ede_rcode
),
1268 isempty(t
->answer_ede_msg
) ? "" : ": ",
1269 strempty(t
->answer_ede_msg
));
1271 t
->answer_dnssec_result
= DNSSEC_UPSTREAM_FAILURE
;
1272 dns_transaction_complete(t
, DNS_TRANSACTION_DNSSEC_FAILED
);
1276 /* These codes probably indicate a transient error. Let's try again. */
1277 if (t
->answer_ede_rcode
== DNS_EDE_RCODE_NOT_READY
) {
1278 log_debug("Server returned error: %s (%s%s%s), retrying transaction.",
1279 FORMAT_DNS_RCODE(dns_packet_rcode(p
)),
1280 FORMAT_DNS_EDE_RCODE(t
->answer_ede_rcode
),
1281 isempty(t
->answer_ede_msg
) ? "" : ": ",
1282 strempty(t
->answer_ede_msg
));
1283 dns_transaction_retry(t
, false);
1287 /* OK, the query failed, but we still shouldn't degrade the feature set for
1289 log_debug("Server returned error: %s (%s%s%s)",
1290 FORMAT_DNS_RCODE(dns_packet_rcode(p
)),
1291 FORMAT_DNS_EDE_RCODE(t
->answer_ede_rcode
),
1292 isempty(t
->answer_ede_msg
) ? "" : ": ",
1293 strempty(t
->answer_ede_msg
));
1297 /* Request failed, immediately try again with reduced features */
1299 if (t
->current_feature_level
<= DNS_SERVER_FEATURE_LEVEL_UDP
) {
1301 /* This was already at UDP feature level? If so, it doesn't make sense to downgrade
1302 * this transaction anymore, but let's see if it might make sense to send the request
1303 * to a different DNS server instead. If not let's process the response, and accept the
1304 * rcode. Note that we don't retry on TCP, since that's a suitable way to mitigate
1305 * packet loss, but is not going to give us better rcodes should we actually have
1306 * managed to get them already at UDP level. */
1308 if (dns_transaction_limited_retry(t
))
1311 /* Give up, accept the rcode */
1312 log_debug("Server returned error: %s", FORMAT_DNS_RCODE(dns_packet_rcode(p
)));
1316 /* SERVFAIL can happen for many reasons and may be transient.
1317 * To avoid unnecessary downgrades retry once with the initial level.
1318 * Check for clamp_feature_level_servfail having an invalid value as a sign that this is the
1319 * first attempt to downgrade. If so, clamp to the current value so that the transaction
1320 * is retried without actually downgrading. If the next try also fails we will downgrade by
1321 * hitting the else branch below. */
1322 if (dns_packet_rcode(p
) == DNS_RCODE_SERVFAIL
&&
1323 t
->clamp_feature_level_servfail
< 0) {
1324 t
->clamp_feature_level_servfail
= t
->current_feature_level
;
1325 log_debug("Server returned error %s, retrying transaction.",
1326 FORMAT_DNS_RCODE(dns_packet_rcode(p
)));
1328 /* Reduce this feature level by one and try again. */
1329 switch (t
->current_feature_level
) {
1330 case DNS_SERVER_FEATURE_LEVEL_TLS_DO
:
1331 t
->clamp_feature_level_servfail
= DNS_SERVER_FEATURE_LEVEL_TLS_PLAIN
;
1333 case DNS_SERVER_FEATURE_LEVEL_TLS_PLAIN
+ 1:
1334 /* Skip plain TLS when TLS is not supported */
1335 t
->clamp_feature_level_servfail
= DNS_SERVER_FEATURE_LEVEL_TLS_PLAIN
- 1;
1338 t
->clamp_feature_level_servfail
= t
->current_feature_level
- 1;
1341 log_debug("Server returned error %s, retrying transaction with reduced feature level %s.",
1342 FORMAT_DNS_RCODE(dns_packet_rcode(p
)),
1343 dns_server_feature_level_to_string(t
->clamp_feature_level_servfail
));
1346 dns_transaction_retry(t
, false /* use the same server */);
1350 if (dns_packet_rcode(p
) == DNS_RCODE_REFUSED
) {
1351 /* This server refused our request? If so, try again, use a different server */
1352 if (t
->answer_ede_rcode
>= 0)
1353 log_debug("Server returned REFUSED (%s), switching servers, and retrying.",
1354 FORMAT_DNS_EDE_RCODE(t
->answer_ede_rcode
));
1356 log_debug("Server returned REFUSED, switching servers, and retrying.");
1358 if (dns_transaction_limited_retry(t
))
1364 if (DNS_PACKET_TC(p
))
1365 dns_server_packet_truncated(t
->server
, t
->current_feature_level
);
1370 case DNS_PROTOCOL_LLMNR
:
1371 case DNS_PROTOCOL_MDNS
:
1372 dns_scope_packet_received(t
->scope
, p
->timestamp
- t
->start_usec
);
1376 assert_not_reached();
1380 /* Report that we successfully received a valid packet with a good rcode after we initially got a bad
1381 * rcode and subsequently downgraded the protocol */
1383 if (IN_SET(dns_packet_rcode(p
), DNS_RCODE_SUCCESS
, DNS_RCODE_NXDOMAIN
) &&
1384 t
->clamp_feature_level_servfail
!= _DNS_SERVER_FEATURE_LEVEL_INVALID
)
1385 dns_server_packet_rcode_downgrade(t
->server
, t
->clamp_feature_level_servfail
);
1387 /* Report that the OPT RR was missing */
1389 dns_server_packet_bad_opt(t
->server
, t
->current_feature_level
);
1391 /* Report that the server didn't copy our query DO bit from request to response */
1392 if (dns_packet_do(t
->sent
) && !dns_packet_do(t
->received
))
1393 dns_server_packet_do_off(t
->server
, t
->current_feature_level
);
1395 /* Report that we successfully received a packet. We keep track of the largest packet
1396 * size/fragment size we got. Which is useful for announcing the EDNS(0) packet size we can
1397 * receive to our server. */
1398 dns_server_packet_received(t
->server
, p
->ipproto
, t
->current_feature_level
, dns_packet_size_unfragmented(p
));
1401 /* See if we know things we didn't know before that indicate we better restart the lookup immediately. */
1402 r
= dns_transaction_maybe_restart(t
);
1405 if (r
> 0) /* Transaction got restarted... */
1408 /* When dealing with protocols other than mDNS only consider responses with equivalent query section
1409 * to the request. For mDNS this check doesn't make sense, because the section 6 of RFC6762 states
1410 * that "Multicast DNS responses MUST NOT contain any questions in the Question Section". */
1411 if (t
->scope
->protocol
!= DNS_PROTOCOL_MDNS
) {
1412 r
= dns_packet_is_reply_for(p
, dns_transaction_key(t
));
1416 dns_transaction_complete(t
, DNS_TRANSACTION_INVALID_REPLY
);
1421 /* Install the answer as answer to the transaction. We ref the answer twice here: the main `answer`
1422 * field is later replaced by the DNSSEC validated subset. The 'answer_auxiliary' field carries the
1423 * original complete record set, including RRSIG and friends. We use this when passing data to
1424 * clients that ask for DNSSEC metadata. */
1425 DNS_ANSWER_REPLACE(t
->answer
, dns_answer_ref(p
->answer
));
1426 t
->answer_rcode
= dns_packet_rcode(p
);
1427 t
->answer_dnssec_result
= _DNSSEC_RESULT_INVALID
;
1428 SET_FLAG(t
->answer_query_flags
, SD_RESOLVED_AUTHENTICATED
, false);
1429 SET_FLAG(t
->answer_query_flags
, SD_RESOLVED_CONFIDENTIAL
, encrypted
);
1431 r
= dns_transaction_fix_rcode(t
);
1435 /* Block GC while starting requests for additional DNSSEC RRs */
1437 r
= dns_transaction_request_dnssec_keys(t
);
1440 /* Maybe the transaction is ready for GC'ing now? If so, free it and return. */
1441 if (!dns_transaction_gc(t
))
1444 /* Requesting additional keys might have resulted in this transaction to fail, since the auxiliary
1445 * request failed for some reason. If so, we are not in pending state anymore, and we should exit
1447 if (t
->state
!= DNS_TRANSACTION_PENDING
)
1452 /* There are DNSSEC transactions pending now. Update the state accordingly. */
1453 t
->state
= DNS_TRANSACTION_VALIDATING
;
1454 dns_transaction_close_connection(t
, true);
1455 dns_transaction_stop_timeout(t
);
1459 dns_transaction_process_dnssec(t
);
1463 dns_transaction_complete_errno(t
, r
);
1466 static int on_dns_packet(sd_event_source
*s
, int fd
, uint32_t revents
, void *userdata
) {
1467 _cleanup_(dns_packet_unrefp
) DnsPacket
*p
= NULL
;
1468 DnsTransaction
*t
= ASSERT_PTR(userdata
);
1473 r
= manager_recv(t
->scope
->manager
, fd
, DNS_PROTOCOL_DNS
, &p
);
1475 if (ERRNO_IS_DISCONNECT(r
)) {
1478 /* UDP connection failures get reported via ICMP and then are possibly delivered to us on the
1479 * next recvmsg(). Treat this like a lost packet. */
1481 log_debug_errno(r
, "Connection failure for DNS UDP packet: %m");
1482 assert_se(sd_event_now(t
->scope
->manager
->event
, CLOCK_BOOTTIME
, &usec
) >= 0);
1483 dns_server_packet_lost(t
->server
, IPPROTO_UDP
, t
->current_feature_level
);
1485 dns_transaction_close_connection(t
, /* use_graveyard = */ false);
1487 if (dns_transaction_limited_retry(t
)) /* Try a different server */
1490 dns_transaction_complete_errno(t
, r
);
1494 /* Spurious wakeup without any data */
1497 r
= dns_packet_validate_reply(p
);
1499 log_debug_errno(r
, "Received invalid DNS packet as response, ignoring: %m");
1503 log_debug("Received inappropriate DNS packet as response, ignoring.");
1507 if (DNS_PACKET_ID(p
) != t
->id
) {
1508 log_debug("Received packet with incorrect transaction ID, ignoring.");
1512 dns_transaction_process_reply(t
, p
, false);
1516 static int dns_transaction_emit_udp(DnsTransaction
*t
) {
1521 if (t
->scope
->protocol
== DNS_PROTOCOL_DNS
) {
1523 r
= dns_transaction_pick_server(t
);
1527 if (manager_server_is_stub(t
->scope
->manager
, t
->server
))
1530 if (t
->current_feature_level
< DNS_SERVER_FEATURE_LEVEL_UDP
|| DNS_SERVER_FEATURE_LEVEL_IS_TLS(t
->current_feature_level
))
1531 return -EAGAIN
; /* Sorry, can't do UDP, try TCP! */
1533 if (!t
->bypass
&& !dns_server_dnssec_supported(t
->server
) && dns_type_is_dnssec(dns_transaction_key(t
)->type
))
1536 if (r
> 0 || t
->dns_udp_fd
< 0) { /* Server changed, or no connection yet. */
1539 dns_transaction_close_connection(t
, true);
1541 /* Before we allocate a new UDP socket, let's process the graveyard a bit to free some fds */
1542 manager_socket_graveyard_process(t
->scope
->manager
);
1544 fd
= dns_scope_socket_udp(t
->scope
, t
->server
);
1548 r
= sd_event_add_io(t
->scope
->manager
->event
, &t
->dns_udp_event_source
, fd
, EPOLLIN
, on_dns_packet
, t
);
1554 (void) sd_event_source_set_description(t
->dns_udp_event_source
, "dns-transaction-udp");
1559 r
= dns_server_adjust_opt(t
->server
, t
->sent
, t
->current_feature_level
);
1564 dns_transaction_close_connection(t
, true);
1566 r
= dns_scope_emit_udp(t
->scope
, t
->dns_udp_fd
, t
->server
? t
->server
->family
: AF_UNSPEC
, t
->sent
);
1570 dns_transaction_reset_answer(t
);
1575 static int on_transaction_timeout(sd_event_source
*s
, usec_t usec
, void *userdata
) {
1576 DnsTransaction
*t
= ASSERT_PTR(userdata
);
1580 t
->seen_timeout
= true;
1582 if (t
->initial_jitter_scheduled
&& !t
->initial_jitter_elapsed
) {
1583 log_debug("Initial jitter phase for transaction %" PRIu16
" elapsed.", t
->id
);
1584 t
->initial_jitter_elapsed
= true;
1586 /* Timeout reached? Increase the timeout for the server used */
1587 switch (t
->scope
->protocol
) {
1589 case DNS_PROTOCOL_DNS
:
1591 dns_server_packet_lost(t
->server
, t
->stream
? IPPROTO_TCP
: IPPROTO_UDP
, t
->current_feature_level
);
1594 case DNS_PROTOCOL_LLMNR
:
1595 case DNS_PROTOCOL_MDNS
:
1596 dns_scope_packet_lost(t
->scope
, usec
- t
->start_usec
);
1600 assert_not_reached();
1603 log_debug("Timeout reached on transaction %" PRIu16
".", t
->id
);
1606 dns_transaction_retry(t
, /* next_server= */ true); /* try a different server, but given this means
1607 * packet loss, let's do so even if we already
1612 static int dns_transaction_setup_timeout(
1614 usec_t timeout_usec
/* relative */,
1615 usec_t next_usec
/* CLOCK_BOOTTIME */) {
1621 dns_transaction_stop_timeout(t
);
1623 r
= sd_event_add_time_relative(
1624 t
->scope
->manager
->event
,
1625 &t
->timeout_event_source
,
1628 on_transaction_timeout
, t
);
1632 (void) sd_event_source_set_description(t
->timeout_event_source
, "dns-transaction-timeout");
1634 t
->next_attempt_after
= next_usec
;
1635 t
->state
= DNS_TRANSACTION_PENDING
;
1639 static usec_t
transaction_get_resend_timeout(DnsTransaction
*t
) {
1643 switch (t
->scope
->protocol
) {
1645 case DNS_PROTOCOL_DNS
:
1648 return TRANSACTION_TCP_TIMEOUT_USEC
;
1650 return TRANSACTION_UDP_TIMEOUT_USEC
;
1652 case DNS_PROTOCOL_MDNS
:
1654 return MDNS_PROBING_INTERVAL_USEC
;
1656 /* See RFC 6762 Section 5.1 suggests that timeout should be a few seconds. */
1657 assert(t
->n_attempts
> 0);
1658 return (1 << (t
->n_attempts
- 1)) * USEC_PER_SEC
;
1660 case DNS_PROTOCOL_LLMNR
:
1661 return t
->scope
->resend_timeout
;
1664 assert_not_reached();
1668 static void dns_transaction_randomize_answer(DnsTransaction
*t
) {
1673 /* Randomizes the order of the answer array. This is done for all cached responses, so that we return
1674 * a different order each time. We do this only for DNS traffic, in order to do some minimal, crappy
1675 * load balancing. We don't do this for LLMNR or mDNS, since the order (preferring link-local
1676 * addresses, and such like) might have meaning there, and load balancing is pointless. */
1678 if (t
->scope
->protocol
!= DNS_PROTOCOL_DNS
)
1681 /* No point in randomizing, if there's just one RR */
1682 if (dns_answer_size(t
->answer
) <= 1)
1685 r
= dns_answer_reserve_or_clone(&t
->answer
, 0);
1686 if (r
< 0) /* If this fails, just don't randomize, this is non-essential stuff after all */
1687 return (void) log_debug_errno(r
, "Failed to clone answer record, not randomizing RR order of answer: %m");
1689 dns_answer_randomize(t
->answer
);
1692 static int dns_transaction_prepare(DnsTransaction
*t
, usec_t ts
) {
1697 /* Returns 0 if dns_transaction_complete() has been called. In that case the transaction and query
1698 * candidate objects may have been invalidated and must not be accessed. Returns 1 if the transaction
1699 * has been prepared. */
1701 dns_transaction_stop_timeout(t
);
1703 if (t
->n_attempts
== 1 && t
->seen_timeout
)
1704 t
->scope
->manager
->n_timeouts_total
++;
1706 if (!dns_scope_network_good(t
->scope
)) {
1707 dns_transaction_complete(t
, DNS_TRANSACTION_NETWORK_DOWN
);
1711 if (t
->n_attempts
>= TRANSACTION_ATTEMPTS_MAX(t
->scope
->protocol
)) {
1712 DnsTransactionState result
;
1714 if (t
->scope
->protocol
== DNS_PROTOCOL_LLMNR
)
1715 /* If we didn't find anything on LLMNR, it's not an error, but a failure to resolve
1717 result
= DNS_TRANSACTION_NOT_FOUND
;
1719 result
= DNS_TRANSACTION_ATTEMPTS_MAX_REACHED
;
1721 dns_transaction_complete(t
, result
);
1725 if (t
->scope
->protocol
== DNS_PROTOCOL_LLMNR
&& t
->tried_stream
) {
1726 /* If we already tried via a stream, then we don't
1727 * retry on LLMNR. See RFC 4795, Section 2.7. */
1728 dns_transaction_complete(t
, DNS_TRANSACTION_ATTEMPTS_MAX_REACHED
);
1735 dns_transaction_reset_answer(t
);
1736 dns_transaction_flush_dnssec_transactions(t
);
1738 /* Check the trust anchor. Do so only on classic DNS, since DNSSEC does not apply otherwise. */
1739 if (t
->scope
->protocol
== DNS_PROTOCOL_DNS
&&
1740 !FLAGS_SET(t
->query_flags
, SD_RESOLVED_NO_TRUST_ANCHOR
)) {
1741 r
= dns_trust_anchor_lookup_positive(&t
->scope
->manager
->trust_anchor
, dns_transaction_key(t
), &t
->answer
);
1745 t
->answer_rcode
= DNS_RCODE_SUCCESS
;
1746 t
->answer_source
= DNS_TRANSACTION_TRUST_ANCHOR
;
1747 SET_FLAG(t
->answer_query_flags
, SD_RESOLVED_AUTHENTICATED
|SD_RESOLVED_CONFIDENTIAL
, true);
1748 dns_transaction_complete(t
, DNS_TRANSACTION_SUCCESS
);
1752 if (dns_name_is_root(dns_resource_key_name(dns_transaction_key(t
))) &&
1753 dns_transaction_key(t
)->type
== DNS_TYPE_DS
) {
1755 /* Hmm, this is a request for the root DS? A DS RR doesn't exist in the root zone,
1756 * and if our trust anchor didn't know it either, this means we cannot do any DNSSEC
1759 if (t
->scope
->dnssec_mode
== DNSSEC_ALLOW_DOWNGRADE
) {
1760 /* We are in downgrade mode. In this case, synthesize an unsigned empty
1761 * response, so that the any lookup depending on this one can continue
1762 * assuming there was no DS, and hence the root zone was unsigned. */
1764 t
->answer_rcode
= DNS_RCODE_SUCCESS
;
1765 t
->answer_source
= DNS_TRANSACTION_TRUST_ANCHOR
;
1766 SET_FLAG(t
->answer_query_flags
, SD_RESOLVED_AUTHENTICATED
, false);
1767 SET_FLAG(t
->answer_query_flags
, SD_RESOLVED_CONFIDENTIAL
, true);
1768 dns_transaction_complete(t
, DNS_TRANSACTION_SUCCESS
);
1770 /* If we are not in downgrade mode, then fail the lookup, because we cannot
1771 * reasonably answer it. There might be DS RRs, but we don't know them, and
1772 * the DNS server won't tell them to us (and even if it would, we couldn't
1773 * validate and trust them. */
1774 dns_transaction_complete(t
, DNS_TRANSACTION_NO_TRUST_ANCHOR
);
1780 /* Check the zone. */
1781 if (!FLAGS_SET(t
->query_flags
, SD_RESOLVED_NO_ZONE
)) {
1782 r
= dns_zone_lookup(&t
->scope
->zone
, dns_transaction_key(t
), dns_scope_ifindex(t
->scope
), &t
->answer
, NULL
, NULL
);
1786 t
->answer_rcode
= DNS_RCODE_SUCCESS
;
1787 t
->answer_source
= DNS_TRANSACTION_ZONE
;
1788 SET_FLAG(t
->answer_query_flags
, SD_RESOLVED_AUTHENTICATED
|SD_RESOLVED_CONFIDENTIAL
, true);
1789 dns_transaction_complete(t
, DNS_TRANSACTION_SUCCESS
);
1794 /* Check the cache. */
1795 if (!FLAGS_SET(t
->query_flags
, SD_RESOLVED_NO_CACHE
)) {
1797 /* Before trying the cache, let's make sure we figured out a server to use. Should this cause
1798 * a change of server this might flush the cache. */
1799 (void) dns_scope_get_dns_server(t
->scope
);
1801 /* Let's then prune all outdated entries */
1802 dns_cache_prune(&t
->scope
->cache
);
1804 /* For the initial attempt or when no stale data is requested, disable serve stale
1805 * and answer the question from the cache (honors ttl property).
1806 * On the second attempt, if StaleRetentionSec is greater than zero,
1807 * try to answer the question using stale date (honors until property) */
1808 uint64_t query_flags
= t
->query_flags
;
1809 if (t
->n_attempts
== 1 || t
->scope
->manager
->stale_retention_usec
== 0)
1810 query_flags
|= SD_RESOLVED_NO_STALE
;
1812 r
= dns_cache_lookup(
1814 dns_transaction_key(t
),
1819 &t
->answer_query_flags
,
1820 &t
->answer_dnssec_result
);
1824 dns_transaction_randomize_answer(t
);
1826 if (t
->bypass
&& t
->scope
->protocol
== DNS_PROTOCOL_DNS
&& !t
->received
)
1827 /* When bypass mode is on, do not use cached data unless it came with a full
1829 dns_transaction_reset_answer(t
);
1831 if (t
->n_attempts
> 1 && !FLAGS_SET(query_flags
, SD_RESOLVED_NO_STALE
)) {
1833 if (t
->answer_rcode
== DNS_RCODE_SUCCESS
) {
1834 if (t
->seen_timeout
)
1835 t
->scope
->manager
->n_timeouts_served_stale_total
++;
1837 t
->scope
->manager
->n_failure_responses_served_stale_total
++;
1840 char key_str
[DNS_RESOURCE_KEY_STRING_MAX
];
1841 log_debug("Serve Stale response rcode=%s for %s",
1842 FORMAT_DNS_RCODE(t
->answer_rcode
),
1843 dns_resource_key_to_string(dns_transaction_key(t
), key_str
, sizeof key_str
));
1846 t
->answer_source
= DNS_TRANSACTION_CACHE
;
1847 if (t
->answer_rcode
== DNS_RCODE_SUCCESS
)
1848 dns_transaction_complete(t
, DNS_TRANSACTION_SUCCESS
);
1851 (void) dns_packet_ede_rcode(t
->received
, &t
->answer_ede_rcode
, &t
->answer_ede_msg
);
1853 dns_transaction_complete(t
, DNS_TRANSACTION_RCODE_FAILURE
);
1860 if (FLAGS_SET(t
->query_flags
, SD_RESOLVED_NO_NETWORK
)) {
1861 dns_transaction_complete(t
, DNS_TRANSACTION_NO_SOURCE
);
1868 static int dns_packet_append_zone(DnsPacket
*p
, DnsTransaction
*t
, DnsResourceKey
*k
, unsigned *nscount
) {
1869 _cleanup_(dns_answer_unrefp
) DnsAnswer
*answer
= NULL
;
1877 if (k
->type
!= DNS_TYPE_ANY
)
1880 r
= dns_zone_lookup(&t
->scope
->zone
, k
, t
->scope
->link
->ifindex
, &answer
, NULL
, &tentative
);
1884 return dns_packet_append_answer(p
, answer
, nscount
);
1887 static int mdns_make_dummy_packet(DnsTransaction
*t
, DnsPacket
**ret_packet
, Set
**ret_keys
) {
1888 _cleanup_(dns_packet_unrefp
) DnsPacket
*p
= NULL
;
1889 _cleanup_set_free_ Set
*keys
= NULL
;
1890 bool add_known_answers
= false;
1897 assert(t
->scope
->protocol
== DNS_PROTOCOL_MDNS
);
1901 r
= dns_packet_new_query(&p
, t
->scope
->protocol
, 0, false);
1905 r
= dns_packet_append_key(p
, dns_transaction_key(t
), 0, NULL
);
1911 if (dns_key_is_shared(dns_transaction_key(t
)))
1912 add_known_answers
= true;
1914 r
= dns_packet_append_zone(p
, t
, dns_transaction_key(t
), NULL
);
1918 /* Save appended keys */
1919 r
= set_ensure_put(&keys
, &dns_resource_key_hash_ops
, dns_transaction_key(t
));
1923 assert_se(sd_event_now(t
->scope
->manager
->event
, CLOCK_BOOTTIME
, &ts
) >= 0);
1925 LIST_FOREACH(transactions_by_scope
, other
, t
->scope
->transactions
) {
1927 /* Skip ourselves */
1931 if (other
->state
!= DNS_TRANSACTION_PENDING
)
1934 if (other
->next_attempt_after
> ts
)
1937 if (!set_contains(keys
, dns_transaction_key(other
))) {
1938 size_t saved_packet_size
;
1940 r
= dns_packet_append_key(p
, dns_transaction_key(other
), 0, &saved_packet_size
);
1941 /* If we can't stuff more questions into the packet, just give up.
1942 * One of the 'other' transactions will fire later and take care of the rest. */
1948 r
= dns_packet_append_zone(p
, t
, dns_transaction_key(other
), NULL
);
1949 if (r
== -EMSGSIZE
) {
1950 dns_packet_truncate(p
, saved_packet_size
);
1956 r
= set_ensure_put(&keys
, &dns_resource_key_hash_ops
, dns_transaction_key(other
));
1961 r
= dns_transaction_prepare(other
, ts
);
1965 /* In this case, not only this transaction, but multiple transactions may be
1966 * freed. Hence, we need to restart the loop. */
1969 usec_t timeout
= transaction_get_resend_timeout(other
);
1970 r
= dns_transaction_setup_timeout(other
, timeout
, usec_add(ts
, timeout
));
1974 if (dns_key_is_shared(dns_transaction_key(other
)))
1975 add_known_answers
= true;
1978 if (qdcount
>= UINT16_MAX
)
1982 DNS_PACKET_HEADER(p
)->qdcount
= htobe16(qdcount
);
1984 /* Append known answers section if we're asking for any shared record */
1985 if (add_known_answers
) {
1986 r
= dns_cache_export_shared_to_packet(&t
->scope
->cache
, p
, ts
, 0);
1991 *ret_packet
= TAKE_PTR(p
);
1992 *ret_keys
= TAKE_PTR(keys
);
1993 return add_known_answers
;
1996 static int dns_transaction_make_packet_mdns(DnsTransaction
*t
) {
1997 _cleanup_(dns_packet_unrefp
) DnsPacket
*p
= NULL
, *dummy
= NULL
;
1998 _cleanup_set_free_ Set
*keys
= NULL
;
1999 bool add_known_answers
;
2005 assert(t
->scope
->protocol
== DNS_PROTOCOL_MDNS
);
2007 /* Discard any previously prepared packet, so we can start over and coalesce again */
2008 t
->sent
= dns_packet_unref(t
->sent
);
2010 /* First, create a dummy packet to calculate the number of known answers to be appended in the first packet. */
2012 r
= mdns_make_dummy_packet(t
, &dummy
, &keys
);
2018 add_known_answers
= r
;
2022 /* Then, create actual packet. */
2023 r
= dns_packet_new_query(&p
, t
->scope
->protocol
, 0, false);
2029 SET_FOREACH(k
, keys
) {
2030 r
= dns_packet_append_key(p
, k
, 0, NULL
);
2035 DNS_PACKET_HEADER(p
)->qdcount
= htobe16(c
);
2038 if (add_known_answers
) {
2041 assert_se(sd_event_now(t
->scope
->manager
->event
, CLOCK_BOOTTIME
, &ts
) >= 0);
2043 r
= dns_cache_export_shared_to_packet(&t
->scope
->cache
, p
, ts
, be16toh(DNS_PACKET_HEADER(dummy
)->ancount
));
2050 SET_FOREACH(k
, keys
) {
2051 r
= dns_packet_append_zone(p
, t
, k
, &c
);
2055 DNS_PACKET_HEADER(p
)->nscount
= htobe16(c
);
2057 t
->sent
= TAKE_PTR(p
);
2061 static int dns_transaction_make_packet(DnsTransaction
*t
) {
2062 _cleanup_(dns_packet_unrefp
) DnsPacket
*p
= NULL
;
2067 if (t
->scope
->protocol
== DNS_PROTOCOL_MDNS
)
2068 return dns_transaction_make_packet_mdns(t
);
2073 if (t
->bypass
&& t
->bypass
->protocol
== t
->scope
->protocol
) {
2074 /* If bypass logic is enabled and the protocol if the original packet and our scope match,
2075 * take the original packet, copy it, and patch in our new ID */
2076 r
= dns_packet_dup(&p
, t
->bypass
);
2080 r
= dns_packet_new_query(
2081 &p
, t
->scope
->protocol
,
2082 /* min_alloc_dsize = */ 0,
2083 /* dnssec_checking_disabled = */ !FLAGS_SET(t
->query_flags
, SD_RESOLVED_NO_VALIDATE
) &&
2084 t
->scope
->dnssec_mode
!= DNSSEC_NO
);
2088 r
= dns_packet_append_key(p
, dns_transaction_key(t
), 0, NULL
);
2092 DNS_PACKET_HEADER(p
)->qdcount
= htobe16(1);
2095 DNS_PACKET_HEADER(p
)->id
= t
->id
;
2097 t
->sent
= TAKE_PTR(p
);
2101 int dns_transaction_go(DnsTransaction
*t
) {
2104 char key_str
[DNS_RESOURCE_KEY_STRING_MAX
];
2108 /* Returns > 0 if the transaction is now pending, returns 0 if could be processed immediately and has
2109 * finished now. In the latter case, the transaction and query candidate objects must not be accessed.
2112 assert_se(sd_event_now(t
->scope
->manager
->event
, CLOCK_BOOTTIME
, &ts
) >= 0);
2114 r
= dns_transaction_prepare(t
, ts
);
2118 log_debug("Firing %s transaction %" PRIu16
" for <%s> scope %s on %s/%s (validate=%s).",
2119 t
->bypass
? "bypass" : "regular",
2121 dns_resource_key_to_string(dns_transaction_key(t
), key_str
, sizeof key_str
),
2122 dns_protocol_to_string(t
->scope
->protocol
),
2123 t
->scope
->link
? t
->scope
->link
->ifname
: "*",
2124 af_to_name_short(t
->scope
->family
),
2125 yes_no(!FLAGS_SET(t
->query_flags
, SD_RESOLVED_NO_VALIDATE
)));
2127 if (!t
->initial_jitter_scheduled
&&
2128 IN_SET(t
->scope
->protocol
, DNS_PROTOCOL_LLMNR
, DNS_PROTOCOL_MDNS
)) {
2131 /* RFC 4795 Section 2.7 suggests all LLMNR queries should be delayed by a random time from 0 to
2133 * RFC 6762 Section 8.1 suggests initial probe queries should be delayed by a random time from
2136 t
->initial_jitter_scheduled
= true;
2139 switch (t
->scope
->protocol
) {
2141 case DNS_PROTOCOL_LLMNR
:
2142 jitter
= random_u64_range(LLMNR_JITTER_INTERVAL_USEC
);
2145 case DNS_PROTOCOL_MDNS
:
2147 jitter
= random_u64_range(MDNS_PROBING_INTERVAL_USEC
);
2152 assert_not_reached();
2155 r
= dns_transaction_setup_timeout(t
, jitter
, ts
);
2159 log_debug("Delaying %s transaction %" PRIu16
" for " USEC_FMT
"us.",
2160 dns_protocol_to_string(t
->scope
->protocol
),
2166 /* Otherwise, we need to ask the network */
2167 r
= dns_transaction_make_packet(t
);
2171 if (t
->scope
->protocol
== DNS_PROTOCOL_LLMNR
&&
2172 (dns_name_endswith(dns_resource_key_name(dns_transaction_key(t
)), "in-addr.arpa") > 0 ||
2173 dns_name_endswith(dns_resource_key_name(dns_transaction_key(t
)), "ip6.arpa") > 0)) {
2175 /* RFC 4795, Section 2.4. says reverse lookups shall
2176 * always be made via TCP on LLMNR */
2177 r
= dns_transaction_emit_tcp(t
);
2179 /* Try via UDP, and if that fails due to large size or lack of
2180 * support try via TCP */
2181 r
= dns_transaction_emit_udp(t
);
2183 log_debug("Sending query via TCP since it is too large.");
2184 else if (r
== -EAGAIN
)
2185 log_debug("Sending query via TCP since UDP isn't supported or DNS-over-TLS is selected.");
2186 else if (r
== -EPERM
)
2187 log_debug("Sending query via TCP since UDP is blocked.");
2188 if (IN_SET(r
, -EMSGSIZE
, -EAGAIN
, -EPERM
))
2189 r
= dns_transaction_emit_tcp(t
);
2192 if (t
->scope
->protocol
!= DNS_PROTOCOL_DNS
)
2195 /* One of our own stub listeners */
2196 log_debug_errno(r
, "Detected that specified DNS server is our own extra listener, switching DNS servers.");
2198 dns_scope_next_dns_server(t
->scope
, t
->server
);
2200 if (dns_scope_get_dns_server(t
->scope
) == t
->server
) {
2201 log_debug_errno(r
, "Still pointing to extra listener after switching DNS servers, refusing operation.");
2202 dns_transaction_complete(t
, DNS_TRANSACTION_STUB_LOOP
);
2206 return dns_transaction_go(t
);
2209 /* No servers to send this to? */
2210 dns_transaction_complete(t
, DNS_TRANSACTION_NO_SERVERS
);
2213 if (r
== -EOPNOTSUPP
) {
2214 /* Tried to ask for DNSSEC RRs, on a server that doesn't do DNSSEC */
2215 dns_transaction_complete(t
, DNS_TRANSACTION_RR_TYPE_UNSUPPORTED
);
2218 if (t
->scope
->protocol
== DNS_PROTOCOL_LLMNR
&& ERRNO_IS_NEG_DISCONNECT(r
)) {
2219 /* On LLMNR, if we cannot connect to a host via TCP when doing reverse lookups. This means we cannot
2220 * answer this request with this protocol. */
2221 dns_transaction_complete(t
, DNS_TRANSACTION_NOT_FOUND
);
2225 if (t
->scope
->protocol
!= DNS_PROTOCOL_DNS
)
2228 /* Couldn't send? Try immediately again, with a new server */
2229 dns_scope_next_dns_server(t
->scope
, t
->server
);
2231 return dns_transaction_go(t
);
2234 usec_t timeout
= transaction_get_resend_timeout(t
);
2235 r
= dns_transaction_setup_timeout(t
, timeout
, usec_add(ts
, timeout
));
2242 static int dns_transaction_find_cyclic(DnsTransaction
*t
, DnsTransaction
*aux
) {
2249 /* Try to find cyclic dependencies between transaction objects */
2254 SET_FOREACH(n
, aux
->dnssec_transactions
) {
2255 r
= dns_transaction_find_cyclic(t
, n
);
2263 static int dns_transaction_add_dnssec_transaction(DnsTransaction
*t
, DnsResourceKey
*key
, DnsTransaction
**ret
) {
2264 _cleanup_(dns_transaction_gcp
) DnsTransaction
*aux
= NULL
;
2271 aux
= dns_scope_find_transaction(t
->scope
, key
, t
->query_flags
);
2273 r
= dns_transaction_new(&aux
, t
->scope
, key
, NULL
, t
->query_flags
);
2277 if (set_contains(t
->dnssec_transactions
, aux
)) {
2282 r
= dns_transaction_find_cyclic(t
, aux
);
2286 char s
[DNS_RESOURCE_KEY_STRING_MAX
], saux
[DNS_RESOURCE_KEY_STRING_MAX
];
2288 return log_debug_errno(SYNTHETIC_ERRNO(ELOOP
),
2289 "Potential cyclic dependency, refusing to add transaction %" PRIu16
" (%s) as dependency for %" PRIu16
" (%s).",
2291 dns_resource_key_to_string(dns_transaction_key(t
), s
, sizeof s
),
2293 dns_resource_key_to_string(dns_transaction_key(aux
), saux
, sizeof saux
));
2297 r
= set_ensure_allocated(&aux
->notify_transactions_done
, NULL
);
2301 r
= set_ensure_put(&t
->dnssec_transactions
, NULL
, aux
);
2305 r
= set_ensure_put(&aux
->notify_transactions
, NULL
, t
);
2307 (void) set_remove(t
->dnssec_transactions
, aux
);
2311 *ret
= TAKE_PTR(aux
);
2315 static int dns_transaction_request_dnssec_rr_full(DnsTransaction
*t
, DnsResourceKey
*key
, DnsTransaction
**ret
) {
2316 _cleanup_(dns_answer_unrefp
) DnsAnswer
*a
= NULL
;
2317 DnsTransaction
*aux
;
2323 /* Try to get the data from the trust anchor */
2324 r
= dns_trust_anchor_lookup_positive(&t
->scope
->manager
->trust_anchor
, key
, &a
);
2328 r
= dns_answer_extend(&t
->validated_keys
, a
);
2337 /* This didn't work, ask for it via the network/cache then. */
2338 r
= dns_transaction_add_dnssec_transaction(t
, key
, &aux
);
2339 if (r
== -ELOOP
) { /* This would result in a cyclic dependency */
2347 if (aux
->state
== DNS_TRANSACTION_NULL
) {
2348 r
= dns_transaction_go(aux
);
2358 static int dns_transaction_request_dnssec_rr(DnsTransaction
*t
, DnsResourceKey
*key
) {
2361 return dns_transaction_request_dnssec_rr_full(t
, key
, NULL
);
2364 static int dns_transaction_negative_trust_anchor_lookup(DnsTransaction
*t
, const char *name
) {
2369 /* Check whether the specified name is in the NTA
2370 * database, either in the global one, or the link-local
2373 r
= dns_trust_anchor_lookup_negative(&t
->scope
->manager
->trust_anchor
, name
);
2377 if (!t
->scope
->link
)
2380 return link_negative_trust_anchor_lookup(t
->scope
->link
, name
);
2383 static int dns_transaction_has_negative_answer(DnsTransaction
*t
) {
2388 /* Checks whether the answer is negative, and lacks NSEC/NSEC3
2389 * RRs to prove it */
2391 r
= dns_transaction_has_positive_answer(t
, NULL
);
2397 /* Is this key explicitly listed as a negative trust anchor?
2398 * If so, it's nothing we need to care about */
2399 r
= dns_transaction_negative_trust_anchor_lookup(t
, dns_resource_key_name(dns_transaction_key(t
)));
2405 static int dns_transaction_is_primary_response(DnsTransaction
*t
, DnsResourceRecord
*rr
) {
2411 /* Check if the specified RR is the "primary" response,
2412 * i.e. either matches the question precisely or is a
2413 * CNAME/DNAME for it. */
2415 r
= dns_resource_key_match_rr(dns_transaction_key(t
), rr
, NULL
);
2419 return dns_resource_key_match_cname_or_dname(dns_transaction_key(t
), rr
->key
, NULL
);
2422 static bool dns_transaction_dnssec_supported(DnsTransaction
*t
) {
2425 /* Checks whether our transaction's DNS server is assumed to be compatible with DNSSEC. Returns false as soon
2426 * as we changed our mind about a server, and now believe it is incompatible with DNSSEC. */
2428 if (t
->scope
->protocol
!= DNS_PROTOCOL_DNS
)
2431 /* If we have picked no server, then we are working from the cache or some other source, and DNSSEC might well
2432 * be supported, hence return true. */
2436 /* Note that we do not check the feature level actually used for the transaction but instead the feature level
2437 * the server is known to support currently, as the transaction feature level might be lower than what the
2438 * server actually supports, since we might have downgraded this transaction's feature level because we got a
2439 * SERVFAIL earlier and wanted to check whether downgrading fixes it. */
2441 return dns_server_dnssec_supported(t
->server
);
2444 static bool dns_transaction_dnssec_supported_full(DnsTransaction
*t
) {
2449 /* Checks whether our transaction our any of the auxiliary transactions couldn't do DNSSEC. */
2451 if (!dns_transaction_dnssec_supported(t
))
2454 SET_FOREACH(dt
, t
->dnssec_transactions
)
2455 if (!dns_transaction_dnssec_supported(dt
))
2461 int dns_transaction_request_dnssec_keys(DnsTransaction
*t
) {
2462 DnsResourceRecord
*rr
;
2464 /* Have we already requested a record that would be sufficient to validate an insecure delegation? */
2465 bool chased_insecure
= false;
2471 * Retrieve all auxiliary RRs for the answer we got, so that
2472 * we can verify signatures or prove that RRs are rightfully
2473 * unsigned. Specifically:
2475 * - For RRSIG we get the matching DNSKEY
2476 * - For DNSKEY we get the matching DS
2477 * - For unsigned SOA/NS we get the matching DS
2478 * - For unsigned CNAME/DNAME/DS we get the parent DS RR
2479 * - For other unsigned RRs we get the matching DS RR
2480 * - For SOA/NS queries with no matching response RR, and no NSEC/NSEC3, the DS RR
2481 * - For DS queries with no matching response RRs, and no NSEC/NSEC3, the parent's DS RR
2482 * - For other queries with no matching response RRs, and no NSEC/NSEC3, the DS RR
2485 if (FLAGS_SET(t
->query_flags
, SD_RESOLVED_NO_VALIDATE
) || t
->scope
->dnssec_mode
== DNSSEC_NO
)
2487 if (t
->answer_source
!= DNS_TRANSACTION_NETWORK
)
2488 return 0; /* We only need to validate stuff from the network */
2489 if (!dns_transaction_dnssec_supported(t
))
2490 return 0; /* If we can't do DNSSEC anyway there's no point in getting the auxiliary RRs */
2492 DNS_ANSWER_FOREACH(rr
, t
->answer
) {
2494 if (dns_type_is_pseudo(rr
->key
->type
))
2497 /* If this RR is in the negative trust anchor, we don't need to validate it. */
2498 r
= dns_transaction_negative_trust_anchor_lookup(t
, dns_resource_key_name(rr
->key
));
2504 switch (rr
->key
->type
) {
2506 case DNS_TYPE_RRSIG
: {
2507 /* For each RRSIG we request the matching DNSKEY */
2508 _cleanup_(dns_resource_key_unrefp
) DnsResourceKey
*dnskey
= NULL
;
2509 DnsTransaction
*aux
;
2511 /* If this RRSIG is about a DNSKEY RR and the
2512 * signer is the same as the owner, then we
2513 * already have the DNSKEY, and we don't have
2514 * to look for more. */
2515 if (rr
->rrsig
.type_covered
== DNS_TYPE_DNSKEY
) {
2516 r
= dns_name_equal(rr
->rrsig
.signer
, dns_resource_key_name(rr
->key
));
2523 /* If the signer is not a parent of our
2524 * original query, then this is about an
2525 * auxiliary RRset, but not anything we asked
2526 * for. In this case we aren't interested,
2527 * because we don't want to request additional
2528 * RRs for stuff we didn't really ask for, and
2529 * also to avoid request loops, where
2530 * additional RRs from one transaction result
2531 * in another transaction whose additional RRs
2532 * point back to the original transaction, and
2534 r
= dns_name_endswith(dns_resource_key_name(dns_transaction_key(t
)), rr
->rrsig
.signer
);
2540 dnskey
= dns_resource_key_new(rr
->key
->class, DNS_TYPE_DNSKEY
, rr
->rrsig
.signer
);
2544 log_debug("Requesting DNSKEY to validate transaction %" PRIu16
" (%s, RRSIG with key tag: %" PRIu16
").",
2545 t
->id
, dns_resource_key_name(rr
->key
), rr
->rrsig
.key_tag
);
2546 r
= dns_transaction_request_dnssec_rr_full(t
, dnskey
, &aux
);
2550 /* If we are requesting a DNSKEY, we can anticipate that we will want the matching DS
2551 * in the near future. Let's request it in advance so we don't have to wait in the
2554 _cleanup_(dns_resource_key_unrefp
) DnsResourceKey
*ds
=
2555 dns_resource_key_new(rr
->key
->class, DNS_TYPE_DS
, dns_resource_key_name(dnskey
));
2558 r
= dns_transaction_request_dnssec_rr(t
, ds
);
2565 case DNS_TYPE_DNSKEY
: {
2566 /* For each DNSKEY we request the matching DS */
2567 _cleanup_(dns_resource_key_unrefp
) DnsResourceKey
*ds
= NULL
;
2569 /* If the DNSKEY we are looking at is not for
2570 * zone we are interested in, nor any of its
2571 * parents, we aren't interested, and don't
2572 * request it. After all, we don't want to end
2573 * up in request loops, and want to keep
2574 * additional traffic down. */
2576 r
= dns_name_endswith(dns_resource_key_name(dns_transaction_key(t
)), dns_resource_key_name(rr
->key
));
2582 ds
= dns_resource_key_new(rr
->key
->class, DNS_TYPE_DS
, dns_resource_key_name(rr
->key
));
2586 log_debug("Requesting DS to validate transaction %" PRIu16
" (%s, DNSKEY with key tag: %" PRIu16
").",
2587 t
->id
, dns_resource_key_name(rr
->key
), dnssec_keytag(rr
, false));
2588 r
= dns_transaction_request_dnssec_rr(t
, ds
);
2597 _cleanup_(dns_resource_key_unrefp
) DnsResourceKey
*ds
= NULL
;
2599 /* For an unsigned SOA or NS, try to acquire
2600 * the matching DS RR, as we are at a zone cut
2601 * then, and whether a DS exists tells us
2602 * whether the zone is signed. Do so only if
2603 * this RR matches our original question,
2606 r
= dns_resource_key_match_rr(dns_transaction_key(t
), rr
, NULL
);
2610 /* Hmm, so this SOA RR doesn't match our original question. In this case, maybe this is
2611 * a negative reply, and we need the SOA RR's TTL in order to cache a negative entry?
2612 * If so, we need to validate it, too. */
2614 r
= dns_answer_match_key(t
->answer
, dns_transaction_key(t
), NULL
);
2617 if (r
> 0) /* positive reply, we won't need the SOA and hence don't need to validate
2621 /* Only bother with this if the SOA/NS RR we are looking at is actually a parent of
2622 * what we are looking for, otherwise there's no value in it for us. */
2623 r
= dns_name_endswith(dns_resource_key_name(dns_transaction_key(t
)), dns_resource_key_name(rr
->key
));
2629 /* If we were looking for the DS RR, don't request it again. */
2630 if (dns_transaction_key(t
)->type
== DNS_TYPE_DS
)
2634 r
= dnssec_has_rrsig(t
->answer
, rr
->key
);
2640 chased_insecure
= true;
2641 ds
= dns_resource_key_new(rr
->key
->class, DNS_TYPE_DS
, dns_resource_key_name(rr
->key
));
2645 log_debug("Requesting DS to validate transaction %" PRIu16
" (%s, unsigned SOA/NS RRset).",
2646 t
->id
, dns_resource_key_name(rr
->key
));
2647 r
= dns_transaction_request_dnssec_rr(t
, ds
);
2655 case DNS_TYPE_CNAME
:
2656 case DNS_TYPE_DNAME
: {
2657 _cleanup_(dns_resource_key_unrefp
) DnsResourceKey
*ds
= NULL
;
2660 /* CNAMEs and DNAMEs cannot be located at a
2661 * zone apex, hence ask for the parent DS for
2662 * unsigned CNAME/DNAME RRs, maybe that's the
2663 * apex. But do all that only if this is
2664 * actually a response to our original
2667 * Similar for DS RRs, which are signed when
2668 * the parent SOA is signed. */
2670 r
= dns_transaction_is_primary_response(t
, rr
);
2676 r
= dnssec_has_rrsig(t
->answer
, rr
->key
);
2682 r
= dns_answer_has_dname_for_cname(t
->answer
, rr
);
2688 name
= dns_resource_key_name(rr
->key
);
2689 r
= dns_name_parent(&name
);
2695 ds
= dns_resource_key_new(rr
->key
->class, DNS_TYPE_DS
, name
);
2699 log_debug("Requesting parent DS to validate transaction %" PRIu16
" (%s, unsigned CNAME/DNAME/DS RRset).",
2700 t
->id
, dns_resource_key_name(rr
->key
));
2701 r
= dns_transaction_request_dnssec_rr(t
, ds
);
2705 if (t
->scope
->dnssec_mode
== DNSSEC_ALLOW_DOWNGRADE
&& dns_name_is_root(name
)) {
2706 _cleanup_(dns_resource_key_unrefp
) DnsResourceKey
*soa
= NULL
;
2707 /* We made it all the way to the root zone. If we are in allow-downgrade
2708 * mode, we need to make at least one request that we can be certain should
2709 * have been signed, to test for servers that are not dnssec aware. */
2710 soa
= dns_resource_key_new(rr
->key
->class, DNS_TYPE_SOA
, name
);
2714 log_debug("Requesting root zone SOA to probe dnssec support.");
2715 r
= dns_transaction_request_dnssec_rr(t
, soa
);
2724 _cleanup_(dns_resource_key_unrefp
) DnsResourceKey
*ds
= NULL
;
2726 /* For other unsigned RRsets (including
2727 * NSEC/NSEC3!), look for proof the zone is
2728 * unsigned, by requesting the DS RR of the
2729 * zone. However, do so only if they are
2730 * directly relevant to our original
2733 r
= dns_transaction_is_primary_response(t
, rr
);
2739 r
= dnssec_has_rrsig(t
->answer
, rr
->key
);
2745 ds
= dns_resource_key_new(rr
->key
->class, DNS_TYPE_DS
, dns_resource_key_name(rr
->key
));
2749 log_debug("Requesting DS to validate transaction %" PRIu16
" (%s, unsigned non-SOA/NS RRset <%s>).",
2750 t
->id
, dns_resource_key_name(rr
->key
), dns_resource_record_to_string(rr
));
2751 r
= dns_transaction_request_dnssec_rr(t
, ds
);
2758 /* Above, we requested everything necessary to validate what
2759 * we got. Now, let's request what we need to validate what we
2762 r
= dns_transaction_has_negative_answer(t
);
2766 const char *name
= dns_resource_key_name(dns_transaction_key(t
));
2767 bool was_signed
= dns_answer_contains_nsec_or_nsec3(t
->answer
);
2769 /* If the response is empty, seek the DS for this name, just in case we're at a zone cut
2770 * already, unless we just requested the DS, in which case we have to ask the parent to make
2773 * If this was an SOA or NS request, we could also skip to the parent, but in real world
2774 * setups there are too many broken DNS servers (Hello, incapdns.net!) where non-terminal
2775 * zones return NXDOMAIN even though they have further children. */
2777 if (chased_insecure
|| was_signed
)
2778 /* In this case we already requested what we need above. */
2780 else if (dns_transaction_key(t
)->type
== DNS_TYPE_DS
)
2781 /* If the DS response is empty, we'll walk up the dns labels requesting DS until we
2782 * find a referral to the SOA or hit it anyway and get a positive DS response. */
2783 if (dns_name_parent(&name
) <= 0)
2787 _cleanup_(dns_resource_key_unrefp
) DnsResourceKey
*ds
= NULL
;
2789 log_debug("Requesting DS (%s %s) to validate transaction %" PRIu16
" (%s empty response).",
2790 glyph(GLYPH_ARROW_RIGHT
), name
, t
->id
,
2791 dns_resource_key_name(dns_transaction_key(t
)));
2793 ds
= dns_resource_key_new(dns_transaction_key(t
)->class, DNS_TYPE_DS
, name
);
2797 r
= dns_transaction_request_dnssec_rr(t
, ds
);
2803 return dns_transaction_dnssec_is_live(t
);
2806 DnsResourceKey
* dns_transaction_key(DnsTransaction
*t
) {
2809 /* Return the lookup key of this transaction. Either takes the lookup key from the bypass packet if
2810 * we are a bypass transaction. Or take the configured key for regular transactions. */
2817 return dns_question_first_key(t
->bypass
->question
);
2820 void dns_transaction_notify(DnsTransaction
*t
, DnsTransaction
*source
) {
2824 /* Invoked whenever any of our auxiliary DNSSEC transactions completed its work. If the state is still PENDING,
2825 we are still in the loop that adds further DNSSEC transactions, hence don't check if we are ready yet. If
2826 the state is VALIDATING however, we should check if we are complete now. */
2828 if (t
->state
== DNS_TRANSACTION_VALIDATING
)
2829 dns_transaction_process_dnssec(t
);
2832 static int dns_transaction_validate_dnskey_by_ds(DnsTransaction
*t
) {
2833 DnsAnswerItem
*item
;
2838 /* Add all DNSKEY RRs from the answer that are validated by DS
2839 * RRs from the list of validated keys to the list of
2840 * validated keys. */
2842 DNS_ANSWER_FOREACH_ITEM(item
, t
->answer
) {
2844 r
= dnssec_verify_dnskey_by_ds_search(item
->rr
, t
->validated_keys
);
2850 /* If so, the DNSKEY is validated too. */
2851 r
= dns_answer_add_extend(&t
->validated_keys
, item
->rr
, item
->ifindex
, item
->flags
|DNS_ANSWER_AUTHENTICATED
, item
->rrsig
);
2859 static int dns_transaction_requires_rrsig(DnsTransaction
*t
, DnsResourceRecord
*rr
) {
2865 /* Checks if the RR we are looking for must be signed with an
2866 * RRSIG. This is used for positive responses. */
2868 if (t
->scope
->dnssec_mode
== DNSSEC_NO
)
2871 if (dns_type_is_pseudo(rr
->key
->type
))
2874 r
= dns_transaction_negative_trust_anchor_lookup(t
, dns_resource_key_name(rr
->key
));
2880 switch (rr
->key
->type
) {
2882 case DNS_TYPE_RRSIG
:
2883 /* RRSIGs are the signatures themselves, they need no signing. */
2890 /* For SOA or NS RRs we look for a matching DS transaction */
2891 SET_FOREACH(dt
, t
->dnssec_transactions
) {
2893 if (dns_transaction_key(dt
)->class != rr
->key
->class)
2895 if (dns_transaction_key(dt
)->type
!= DNS_TYPE_DS
)
2898 r
= dns_name_endswith(dns_resource_key_name(rr
->key
), dns_resource_key_name(dns_transaction_key(dt
)));
2904 /* We found a DS transactions for the SOA/NS
2905 * RRs we are looking at. If it discovered signed DS
2906 * RRs, then we need to be signed, too. */
2908 if (!FLAGS_SET(dt
->answer_query_flags
, SD_RESOLVED_AUTHENTICATED
))
2911 return dns_answer_match_key(dt
->answer
, dns_transaction_key(dt
), NULL
);
2914 /* We found nothing that proves this is safe to leave
2915 * this unauthenticated, hence ask inist on
2916 * authentication. */
2921 case DNS_TYPE_CNAME
:
2922 case DNS_TYPE_DNAME
: {
2923 const char *parent
= NULL
;
2927 * CNAME/DNAME RRs cannot be located at a zone apex, hence look directly for the parent DS.
2929 * DS RRs are signed if the parent is signed, hence also look at the parent DS
2932 SET_FOREACH(dt
, t
->dnssec_transactions
) {
2934 if (dns_transaction_key(dt
)->class != rr
->key
->class)
2936 if (dns_transaction_key(dt
)->type
!= DNS_TYPE_DS
)
2940 parent
= dns_resource_key_name(rr
->key
);
2941 r
= dns_name_parent(&parent
);
2945 if (rr
->key
->type
== DNS_TYPE_DS
)
2948 /* A CNAME/DNAME without a parent? That's sooo weird. */
2949 return log_debug_errno(SYNTHETIC_ERRNO(EBADMSG
),
2950 "Transaction %" PRIu16
" claims CNAME/DNAME at root. Refusing.", t
->id
);
2954 r
= dns_name_endswith(parent
, dns_resource_key_name(dns_transaction_key(dt
)));
2960 if (!FLAGS_SET(dt
->answer_query_flags
, SD_RESOLVED_AUTHENTICATED
))
2963 /* We expect this to be signed when the DS record exists, and don't expect it to be
2964 * signed when the DS record is proven not to exist. */
2965 return dns_answer_match_key(dt
->answer
, dns_transaction_key(dt
), NULL
);
2974 /* Any other kind of RR (including DNSKEY/NSEC/NSEC3). Let's see if our DS lookup was authenticated */
2976 SET_FOREACH(dt
, t
->dnssec_transactions
) {
2977 if (dns_transaction_key(dt
)->class != rr
->key
->class)
2979 if (dns_transaction_key(dt
)->type
!= DNS_TYPE_DS
)
2982 r
= dns_name_endswith(dns_resource_key_name(rr
->key
), dns_resource_key_name(dns_transaction_key(dt
)));
2988 if (!FLAGS_SET(dt
->answer_query_flags
, SD_RESOLVED_AUTHENTICATED
))
2991 /* We expect this to be signed when the DS record exists, and don't expect it to be
2992 * signed when the DS record is proven not to exist. */
2993 return dns_answer_match_key(dt
->answer
, dns_transaction_key(dt
), NULL
);
3000 static int dns_transaction_in_private_tld(DnsTransaction
*t
, const DnsResourceKey
*key
) {
3005 /* If DNSSEC downgrade mode is on, checks whether the
3006 * specified RR is one level below a TLD we have proven not to
3007 * exist. In such a case we assume that this is a private
3008 * domain, and permit it.
3010 * This detects cases like the Fritz!Box router networks. Each
3011 * Fritz!Box router serves a private "fritz.box" zone, in the
3012 * non-existing TLD "box". Requests for the "fritz.box" domain
3013 * are served by the router itself, while requests for the
3014 * "box" domain will result in NXDOMAIN.
3016 * Note that this logic is unable to detect cases where a
3017 * router serves a private DNS zone directly under
3018 * non-existing TLD. In such a case we cannot detect whether
3019 * the TLD is supposed to exist or not, as all requests we
3020 * make for it will be answered by the router's zone, and not
3021 * by the root zone. */
3025 if (t
->scope
->dnssec_mode
!= DNSSEC_ALLOW_DOWNGRADE
)
3026 return false; /* In strict DNSSEC mode what doesn't exist, doesn't exist */
3028 tld
= dns_resource_key_name(key
);
3029 r
= dns_name_parent(&tld
);
3033 return false; /* Already the root domain */
3035 if (!dns_name_is_single_label(tld
))
3038 SET_FOREACH(dt
, t
->dnssec_transactions
) {
3040 if (dns_transaction_key(dt
)->class != key
->class)
3043 r
= dns_name_equal(dns_resource_key_name(dns_transaction_key(dt
)), tld
);
3049 /* We found an auxiliary lookup we did for the TLD. If
3050 * that returned with NXDOMAIN, we know the TLD didn't
3051 * exist, and hence this might be a private zone. */
3053 return dt
->answer_rcode
== DNS_RCODE_NXDOMAIN
;
3059 static int dns_transaction_requires_nsec(DnsTransaction
*t
) {
3060 char key_str
[DNS_RESOURCE_KEY_STRING_MAX
];
3067 /* Checks if we need to insist on NSEC/NSEC3 RRs for proving
3068 * this negative reply */
3070 if (t
->scope
->dnssec_mode
== DNSSEC_NO
)
3073 if (dns_type_is_pseudo(dns_transaction_key(t
)->type
))
3076 r
= dns_transaction_negative_trust_anchor_lookup(t
, dns_resource_key_name(dns_transaction_key(t
)));
3082 r
= dns_transaction_in_private_tld(t
, dns_transaction_key(t
));
3086 /* The lookup is from a TLD that is proven not to
3087 * exist, and we are in downgrade mode, hence ignore
3088 * that fact that we didn't get any NSEC RRs. */
3090 log_info("Detected a negative query %s in a private DNS zone, permitting unsigned response.",
3091 dns_resource_key_to_string(dns_transaction_key(t
), key_str
, sizeof key_str
));
3095 name
= dns_resource_key_name(dns_transaction_key(t
));
3097 /* For all other RRs we check the DS on the same level to see
3098 * if it's signed. */
3100 SET_FOREACH(dt
, t
->dnssec_transactions
) {
3101 if (dns_transaction_key(dt
)->class != dns_transaction_key(t
)->class)
3103 if (dns_transaction_key(dt
)->type
!= DNS_TYPE_DS
)
3106 r
= dns_name_endswith(name
, dns_resource_key_name(dns_transaction_key(dt
)));
3112 if (!FLAGS_SET(dt
->answer_query_flags
, SD_RESOLVED_AUTHENTICATED
))
3115 /* We expect this to be signed when the DS record exists, and don't expect it to be signed
3116 * when the DS record is proven not to exist. */
3117 return dns_answer_match_key(dt
->answer
, dns_transaction_key(dt
), NULL
);
3120 /* If in doubt, require NSEC/NSEC3 */
3124 static int dns_transaction_dnskey_authenticated(DnsTransaction
*t
, DnsResourceRecord
*rr
) {
3125 DnsResourceRecord
*rrsig
;
3129 /* Checks whether any of the DNSKEYs used for the RRSIGs for
3130 * the specified RRset is authenticated (i.e. has a matching
3133 r
= dns_transaction_negative_trust_anchor_lookup(t
, dns_resource_key_name(rr
->key
));
3139 DNS_ANSWER_FOREACH(rrsig
, t
->answer
) {
3142 r
= dnssec_key_match_rrsig(rr
->key
, rrsig
);
3148 SET_FOREACH(dt
, t
->dnssec_transactions
) {
3150 if (dns_transaction_key(dt
)->class != rr
->key
->class)
3153 if (dns_transaction_key(dt
)->type
== DNS_TYPE_DNSKEY
) {
3155 r
= dns_name_equal(dns_resource_key_name(dns_transaction_key(dt
)), rrsig
->rrsig
.signer
);
3161 /* OK, we found an auxiliary DNSKEY lookup. If that lookup is authenticated,
3164 if (FLAGS_SET(dt
->answer_query_flags
, SD_RESOLVED_AUTHENTICATED
))
3169 } else if (dns_transaction_key(dt
)->type
== DNS_TYPE_DS
) {
3171 r
= dns_name_equal(dns_resource_key_name(dns_transaction_key(dt
)), rrsig
->rrsig
.signer
);
3177 /* OK, we found an auxiliary DS lookup. If that lookup is authenticated and
3178 * non-zero, we won! */
3180 if (!FLAGS_SET(dt
->answer_query_flags
, SD_RESOLVED_AUTHENTICATED
))
3183 return dns_answer_match_key(dt
->answer
, dns_transaction_key(dt
), NULL
);
3188 return found
? false : -ENXIO
;
3191 static int dns_transaction_known_signed(DnsTransaction
*t
, DnsResourceRecord
*rr
) {
3195 /* We know that the root domain is signed, hence if it appears
3196 * not to be signed, there's a problem with the DNS server */
3198 return rr
->key
->class == DNS_CLASS_IN
&&
3199 dns_name_is_root(dns_resource_key_name(rr
->key
));
3202 static int dns_transaction_check_revoked_trust_anchors(DnsTransaction
*t
) {
3203 DnsResourceRecord
*rr
;
3208 /* Maybe warn the user that we encountered a revoked DNSKEY
3209 * for a key from our trust anchor. Note that we don't care
3210 * whether the DNSKEY can be authenticated or not. It's
3211 * sufficient if it is self-signed. */
3213 DNS_ANSWER_FOREACH(rr
, t
->answer
) {
3214 r
= dns_trust_anchor_check_revoked(&t
->scope
->manager
->trust_anchor
, rr
, t
->answer
);
3222 static int dns_transaction_invalidate_revoked_keys(DnsTransaction
*t
) {
3228 /* Removes all DNSKEY/DS objects from t->validated_keys that
3229 * our trust anchors database considers revoked. */
3232 DnsResourceRecord
*rr
;
3236 DNS_ANSWER_FOREACH(rr
, t
->validated_keys
) {
3237 r
= dns_trust_anchor_is_revoked(&t
->scope
->manager
->trust_anchor
, rr
);
3241 r
= dns_answer_remove_by_rr(&t
->validated_keys
, rr
);
3255 static int dns_transaction_copy_validated(DnsTransaction
*t
) {
3261 /* Copy all validated RRs from the auxiliary DNSSEC transactions into our set of validated RRs */
3263 SET_FOREACH(dt
, t
->dnssec_transactions
) {
3265 if (DNS_TRANSACTION_IS_LIVE(dt
->state
))
3268 if (!FLAGS_SET(dt
->answer_query_flags
, SD_RESOLVED_AUTHENTICATED
))
3271 r
= dns_answer_extend(&t
->validated_keys
, dt
->answer
);
3280 DNSSEC_PHASE_DNSKEY
, /* Phase #1, only validate DNSKEYs */
3281 DNSSEC_PHASE_NSEC
, /* Phase #2, only validate NSEC+NSEC3 */
3282 DNSSEC_PHASE_ALL
, /* Phase #3, validate everything else */
3285 static int dnssec_validate_records(
3289 unsigned *nvalidations
,
3290 DnsAnswer
**validated
) {
3292 DnsResourceRecord
*rr
;
3295 assert(nvalidations
);
3297 /* Returns negative on error, 0 if validation failed, 1 to restart validation, 2 when finished. */
3299 DNS_ANSWER_FOREACH(rr
, t
->answer
) {
3300 _unused_
_cleanup_(dns_resource_record_unrefp
) DnsResourceRecord
*rr_ref
= dns_resource_record_ref(rr
);
3301 DnsResourceRecord
*rrsig
= NULL
;
3302 DnssecResult result
;
3304 switch (rr
->key
->type
) {
3305 case DNS_TYPE_RRSIG
:
3308 case DNS_TYPE_DNSKEY
:
3309 /* We validate DNSKEYs only in the DNSKEY and ALL phases */
3310 if (phase
== DNSSEC_PHASE_NSEC
)
3315 case DNS_TYPE_NSEC3
:
3318 /* We validate NSEC/NSEC3 only in the NSEC and ALL phases */
3319 if (phase
== DNSSEC_PHASE_DNSKEY
)
3324 /* We validate all other RRs only in the ALL phases */
3325 if (phase
!= DNSSEC_PHASE_ALL
)
3329 r
= dnssec_verify_rrset_search(
3340 log_debug("Looking at %s: %s", strna(dns_resource_record_to_string(rr
)), dnssec_result_to_string(result
));
3342 if (result
== DNSSEC_VALIDATED
) {
3345 if (rr
->key
->type
== DNS_TYPE_DNSKEY
) {
3346 /* If we just validated a DNSKEY RRset, then let's add these keys to
3347 * the set of validated keys for this transaction. */
3349 r
= dns_answer_copy_by_key(&t
->validated_keys
, t
->answer
, rr
->key
, DNS_ANSWER_AUTHENTICATED
, rrsig
);
3353 /* Some of the DNSKEYs we just added might already have been revoked,
3354 * remove them again in that case. */
3355 r
= dns_transaction_invalidate_revoked_keys(t
);
3360 /* Add the validated RRset to the new list of validated RRsets, and remove it from
3361 * the unvalidated RRsets. We mark the RRset as authenticated and cacheable. */
3362 r
= dns_answer_move_by_key(validated
, &t
->answer
, rr
->key
, DNS_ANSWER_AUTHENTICATED
|DNS_ANSWER_CACHEABLE
, rrsig
);
3366 manager_dnssec_verdict(t
->scope
->manager
, DNSSEC_SECURE
, rr
->key
);
3368 /* Exit the loop, we dropped something from the answer, start from the beginning */
3372 /* If we haven't read all DNSKEYs yet a negative result of the validation is irrelevant, as
3373 * there might be more DNSKEYs coming. Similar, if we haven't read all NSEC/NSEC3 RRs yet,
3374 * we cannot do positive wildcard proofs yet, as those require the NSEC/NSEC3 RRs. */
3375 if (phase
!= DNSSEC_PHASE_ALL
)
3378 if (result
== DNSSEC_VALIDATED_WILDCARD
) {
3379 bool authenticated
= false;
3384 /* This RRset validated, but as a wildcard. This means we need
3385 * to prove via NSEC/NSEC3 that no matching non-wildcard RR exists. */
3387 /* First step, determine the source of synthesis */
3388 r
= dns_resource_record_source(rrsig
, &source
);
3392 r
= dnssec_test_positive_wildcard(*validated
,
3393 dns_resource_key_name(rr
->key
),
3395 rrsig
->rrsig
.signer
,
3398 /* Unless the NSEC proof showed that the key really doesn't exist something is off. */
3400 result
= DNSSEC_INVALID
;
3402 r
= dns_answer_move_by_key(
3406 authenticated
? (DNS_ANSWER_AUTHENTICATED
|DNS_ANSWER_CACHEABLE
) : 0,
3411 manager_dnssec_verdict(t
->scope
->manager
, authenticated
? DNSSEC_SECURE
: DNSSEC_INSECURE
, rr
->key
);
3413 /* Exit the loop, we dropped something from the answer, start from the beginning */
3418 if (result
== DNSSEC_NO_SIGNATURE
) {
3419 r
= dns_transaction_requires_rrsig(t
, rr
);
3423 /* Data does not require signing. In that case, just copy it over,
3424 * but remember that this is by no means authenticated. */
3425 r
= dns_answer_move_by_key(
3434 manager_dnssec_verdict(t
->scope
->manager
, DNSSEC_INSECURE
, rr
->key
);
3438 r
= dns_transaction_known_signed(t
, rr
);
3442 /* This is an RR we know has to be signed. If it isn't this means
3443 * the server is not attaching RRSIGs, hence complain. */
3445 dns_server_packet_rrsig_missing(t
->server
, t
->current_feature_level
);
3447 if (t
->scope
->dnssec_mode
== DNSSEC_ALLOW_DOWNGRADE
) {
3449 /* Downgrading is OK? If so, just consider the information unsigned */
3451 r
= dns_answer_move_by_key(validated
, &t
->answer
, rr
->key
, 0, NULL
);
3455 manager_dnssec_verdict(t
->scope
->manager
, DNSSEC_INSECURE
, rr
->key
);
3459 /* Otherwise, fail */
3460 t
->answer_dnssec_result
= DNSSEC_INCOMPATIBLE_SERVER
;
3464 r
= dns_transaction_in_private_tld(t
, rr
->key
);
3468 char s
[DNS_RESOURCE_KEY_STRING_MAX
];
3470 /* The data is from a TLD that is proven not to exist, and we are in downgrade
3471 * mode, hence ignore the fact that this was not signed. */
3473 log_info("Detected RRset %s is in a private DNS zone, permitting unsigned RRs.",
3474 dns_resource_key_to_string(rr
->key
, s
, sizeof s
));
3476 r
= dns_answer_move_by_key(validated
, &t
->answer
, rr
->key
, 0, NULL
);
3480 manager_dnssec_verdict(t
->scope
->manager
, DNSSEC_INSECURE
, rr
->key
);
3485 /* https://datatracker.ietf.org/doc/html/rfc6840#section-5.2 */
3486 if (result
== DNSSEC_UNSUPPORTED_ALGORITHM
) {
3487 r
= dns_answer_move_by_key(validated
, &t
->answer
, rr
->key
, 0, NULL
);
3491 manager_dnssec_verdict(t
->scope
->manager
, DNSSEC_INSECURE
, rr
->key
);
3497 DNSSEC_SIGNATURE_EXPIRED
)) {
3499 r
= dns_transaction_dnskey_authenticated(t
, rr
);
3500 if (r
< 0 && r
!= -ENXIO
)
3503 /* The DNSKEY transaction was not authenticated, this means there's
3504 * no DS for this, which means it's OK if no keys are found for this signature. */
3506 r
= dns_answer_move_by_key(validated
, &t
->answer
, rr
->key
, 0, NULL
);
3510 manager_dnssec_verdict(t
->scope
->manager
, DNSSEC_INSECURE
, rr
->key
);
3515 r
= dns_transaction_is_primary_response(t
, rr
);
3519 /* Look for a matching DNAME for this CNAME */
3520 r
= dns_answer_has_dname_for_cname(t
->answer
, rr
);
3524 /* Also look among the stuff we already validated */
3525 r
= dns_answer_has_dname_for_cname(*validated
, rr
);
3533 DNSSEC_SIGNATURE_EXPIRED
,
3534 DNSSEC_NO_SIGNATURE
))
3535 manager_dnssec_verdict(t
->scope
->manager
, DNSSEC_BOGUS
, rr
->key
);
3536 else /* DNSSEC_MISSING_KEY, DNSSEC_UNSUPPORTED_ALGORITHM,
3537 or DNSSEC_TOO_MANY_VALIDATIONS */
3538 manager_dnssec_verdict(t
->scope
->manager
, DNSSEC_INDETERMINATE
, rr
->key
);
3540 /* This is a primary response to our question, and it failed validation.
3542 t
->answer_dnssec_result
= result
;
3546 /* This is a primary response, but we do have a DNAME RR
3547 * in the RR that can replay this CNAME, hence rely on
3548 * that, and we can remove the CNAME in favour of it. */
3551 /* This is just some auxiliary data. Just remove the RRset and continue. */
3552 r
= dns_answer_remove_by_key(&t
->answer
, rr
->key
);
3556 /* We dropped something from the answer, start from the beginning. */
3560 return 2; /* Finito. */
3563 int dns_transaction_validate_dnssec(DnsTransaction
*t
) {
3564 _cleanup_(dns_answer_unrefp
) DnsAnswer
*validated
= NULL
;
3566 DnsAnswerFlags flags
;
3568 char key_str
[DNS_RESOURCE_KEY_STRING_MAX
];
3572 /* We have now collected all DS and DNSKEY RRs in t->validated_keys, let's see which RRs we can now
3573 * authenticate with that. */
3575 if (FLAGS_SET(t
->query_flags
, SD_RESOLVED_NO_VALIDATE
) || t
->scope
->dnssec_mode
== DNSSEC_NO
)
3578 /* Already validated */
3579 if (t
->answer_dnssec_result
!= _DNSSEC_RESULT_INVALID
)
3582 /* Our own stuff needs no validation */
3583 if (IN_SET(t
->answer_source
, DNS_TRANSACTION_ZONE
, DNS_TRANSACTION_TRUST_ANCHOR
)) {
3584 t
->answer_dnssec_result
= DNSSEC_VALIDATED
;
3585 SET_FLAG(t
->answer_query_flags
, SD_RESOLVED_AUTHENTICATED
, true);
3589 /* Cached stuff is not affected by validation. */
3590 if (t
->answer_source
!= DNS_TRANSACTION_NETWORK
)
3593 if (!dns_transaction_dnssec_supported_full(t
)) {
3594 /* The server does not support DNSSEC, or doesn't augment responses with RRSIGs. */
3595 t
->answer_dnssec_result
= DNSSEC_INCOMPATIBLE_SERVER
;
3596 log_debug("Not validating response for %" PRIu16
", used server feature level does not support DNSSEC.", t
->id
);
3600 log_debug("Validating response from transaction %" PRIu16
" (%s).",
3602 dns_resource_key_to_string(dns_transaction_key(t
), key_str
, sizeof key_str
));
3604 /* First, see if this response contains any revoked trust
3605 * anchors we care about */
3606 r
= dns_transaction_check_revoked_trust_anchors(t
);
3610 /* Third, copy all RRs we acquired successfully from auxiliary RRs over. */
3611 r
= dns_transaction_copy_validated(t
);
3615 /* Second, see if there are DNSKEYs we already know a
3616 * validated DS for. */
3617 r
= dns_transaction_validate_dnskey_by_ds(t
);
3621 /* Fourth, remove all DNSKEY and DS RRs again that our trust
3622 * anchor says are revoked. After all we might have marked
3623 * some keys revoked above, but they might still be lingering
3624 * in our validated_keys list. */
3625 r
= dns_transaction_invalidate_revoked_keys(t
);
3629 phase
= DNSSEC_PHASE_DNSKEY
;
3630 for (unsigned nvalidations
= 0;;) {
3631 bool have_nsec
= false;
3633 r
= dnssec_validate_records(t
, phase
, &have_nsec
, &nvalidations
, &validated
);
3635 DNS_ANSWER_REPLACE(t
->answer
, TAKE_PTR(validated
));
3639 if (nvalidations
> DNSSEC_VALIDATION_MAX
) {
3640 /* This reply requires an onerous number of signature validations to verify. Let's
3641 * not waste our time trying, as this shouldn't happen for well-behaved domains
3643 t
->answer_dnssec_result
= DNSSEC_TOO_MANY_VALIDATIONS
;
3644 DNS_ANSWER_REPLACE(t
->answer
, TAKE_PTR(validated
));
3648 /* Try again as long as we managed to achieve something */
3652 if (phase
== DNSSEC_PHASE_DNSKEY
&& have_nsec
) {
3653 /* OK, we processed all DNSKEYs, and there are NSEC/NSEC3 RRs, look at those now. */
3654 phase
= DNSSEC_PHASE_NSEC
;
3658 if (phase
!= DNSSEC_PHASE_ALL
) {
3659 /* OK, we processed all DNSKEYs and NSEC/NSEC3 RRs, look at all the rest now.
3660 * Note that in this third phase we start to remove RRs we couldn't validate. */
3661 phase
= DNSSEC_PHASE_ALL
;
3669 DNS_ANSWER_REPLACE(t
->answer
, TAKE_PTR(validated
));
3671 /* At this point the answer only contains validated
3672 * RRsets. Now, let's see if it actually answers the question
3673 * we asked. If so, great! If it doesn't, then see if
3674 * NSEC/NSEC3 can prove this. */
3675 r
= dns_transaction_has_positive_answer(t
, &flags
);
3677 /* Yes, it answers the question! */
3679 if (flags
& DNS_ANSWER_AUTHENTICATED
) {
3680 /* The answer is fully authenticated, yay. */
3681 t
->answer_dnssec_result
= DNSSEC_VALIDATED
;
3682 t
->answer_rcode
= DNS_RCODE_SUCCESS
;
3683 SET_FLAG(t
->answer_query_flags
, SD_RESOLVED_AUTHENTICATED
, true);
3685 /* The answer is not fully authenticated. */
3686 t
->answer_dnssec_result
= DNSSEC_UNSIGNED
;
3687 SET_FLAG(t
->answer_query_flags
, SD_RESOLVED_AUTHENTICATED
, false);
3690 } else if (r
== 0) {
3691 DnssecNsecResult nr
;
3692 bool authenticated
= false;
3694 /* Bummer! Let's check NSEC/NSEC3 */
3695 r
= dnssec_nsec_test(t
->answer
, dns_transaction_key(t
), &nr
, &authenticated
, &t
->answer_nsec_ttl
);
3701 case DNSSEC_NSEC_NXDOMAIN
:
3702 /* NSEC proves the domain doesn't exist. Very good. */
3703 log_debug("Proved NXDOMAIN via NSEC/NSEC3 for transaction %u (%s)", t
->id
, key_str
);
3704 t
->answer_dnssec_result
= DNSSEC_VALIDATED
;
3705 t
->answer_rcode
= DNS_RCODE_NXDOMAIN
;
3706 SET_FLAG(t
->answer_query_flags
, SD_RESOLVED_AUTHENTICATED
, authenticated
);
3708 manager_dnssec_verdict(t
->scope
->manager
, authenticated
? DNSSEC_SECURE
: DNSSEC_INSECURE
, dns_transaction_key(t
));
3711 case DNSSEC_NSEC_NODATA
:
3712 /* NSEC proves that there's no data here, very good. */
3713 log_debug("Proved NODATA via NSEC/NSEC3 for transaction %u (%s)", t
->id
, key_str
);
3714 t
->answer_dnssec_result
= DNSSEC_VALIDATED
;
3715 t
->answer_rcode
= DNS_RCODE_SUCCESS
;
3716 SET_FLAG(t
->answer_query_flags
, SD_RESOLVED_AUTHENTICATED
, authenticated
);
3718 manager_dnssec_verdict(t
->scope
->manager
, authenticated
? DNSSEC_SECURE
: DNSSEC_INSECURE
, dns_transaction_key(t
));
3721 case DNSSEC_NSEC_OPTOUT
:
3722 /* NSEC3 says the data might not be signed */
3723 log_debug("Data is NSEC3 opt-out via NSEC/NSEC3 for transaction %u (%s)", t
->id
, key_str
);
3724 t
->answer_dnssec_result
= DNSSEC_UNSIGNED
;
3725 SET_FLAG(t
->answer_query_flags
, SD_RESOLVED_AUTHENTICATED
, false);
3727 manager_dnssec_verdict(t
->scope
->manager
, DNSSEC_INSECURE
, dns_transaction_key(t
));
3730 case DNSSEC_NSEC_NO_RR
:
3731 /* No NSEC data? Bummer! */
3733 r
= dns_transaction_requires_nsec(t
);
3737 t
->answer_dnssec_result
= DNSSEC_NO_SIGNATURE
;
3738 manager_dnssec_verdict(t
->scope
->manager
, DNSSEC_BOGUS
, dns_transaction_key(t
));
3740 t
->answer_dnssec_result
= DNSSEC_UNSIGNED
;
3741 SET_FLAG(t
->answer_query_flags
, SD_RESOLVED_AUTHENTICATED
, false);
3742 manager_dnssec_verdict(t
->scope
->manager
, DNSSEC_INSECURE
, dns_transaction_key(t
));
3747 case DNSSEC_NSEC_UNSUPPORTED_ALGORITHM
:
3748 /* We don't know the NSEC3 algorithm used? */
3749 t
->answer_dnssec_result
= DNSSEC_UNSUPPORTED_ALGORITHM
;
3750 manager_dnssec_verdict(t
->scope
->manager
, DNSSEC_INDETERMINATE
, dns_transaction_key(t
));
3753 case DNSSEC_NSEC_FOUND
:
3754 case DNSSEC_NSEC_CNAME
:
3755 /* NSEC says it needs to be there, but we couldn't find it? Bummer! */
3756 t
->answer_dnssec_result
= DNSSEC_NSEC_MISMATCH
;
3757 manager_dnssec_verdict(t
->scope
->manager
, DNSSEC_BOGUS
, dns_transaction_key(t
));
3761 assert_not_reached();
3768 static const char* const dns_transaction_state_table
[_DNS_TRANSACTION_STATE_MAX
] = {
3769 [DNS_TRANSACTION_NULL
] = "null",
3770 [DNS_TRANSACTION_PENDING
] = "pending",
3771 [DNS_TRANSACTION_VALIDATING
] = "validating",
3772 [DNS_TRANSACTION_RCODE_FAILURE
] = "rcode-failure",
3773 [DNS_TRANSACTION_SUCCESS
] = "success",
3774 [DNS_TRANSACTION_NO_SERVERS
] = "no-servers",
3775 [DNS_TRANSACTION_TIMEOUT
] = "timeout",
3776 [DNS_TRANSACTION_ATTEMPTS_MAX_REACHED
] = "attempts-max-reached",
3777 [DNS_TRANSACTION_INVALID_REPLY
] = "invalid-reply",
3778 [DNS_TRANSACTION_ERRNO
] = "errno",
3779 [DNS_TRANSACTION_ABORTED
] = "aborted",
3780 [DNS_TRANSACTION_DNSSEC_FAILED
] = "dnssec-failed",
3781 [DNS_TRANSACTION_NO_TRUST_ANCHOR
] = "no-trust-anchor",
3782 [DNS_TRANSACTION_RR_TYPE_UNSUPPORTED
] = "rr-type-unsupported",
3783 [DNS_TRANSACTION_NETWORK_DOWN
] = "network-down",
3784 [DNS_TRANSACTION_NOT_FOUND
] = "not-found",
3785 [DNS_TRANSACTION_NO_SOURCE
] = "no-source",
3786 [DNS_TRANSACTION_STUB_LOOP
] = "stub-loop",
3788 DEFINE_STRING_TABLE_LOOKUP(dns_transaction_state
, DnsTransactionState
);
3790 static const char* const dns_transaction_source_table
[_DNS_TRANSACTION_SOURCE_MAX
] = {
3791 [DNS_TRANSACTION_NETWORK
] = "network",
3792 [DNS_TRANSACTION_CACHE
] = "cache",
3793 [DNS_TRANSACTION_ZONE
] = "zone",
3794 [DNS_TRANSACTION_TRUST_ANCHOR
] = "trust-anchor",
3796 DEFINE_STRING_TABLE_LOOKUP(dns_transaction_source
, DnsTransactionSource
);