1 /* SPDX-License-Identifier: LGPL-2.1-or-later */
3 #include "sd-messages.h"
6 #include "alloc-util.h"
7 #include "dns-domain.h"
8 #include "errno-list.h"
9 #include "errno-util.h"
11 #include "glyph-util.h"
12 #include "random-util.h"
13 #include "resolved-dns-cache.h"
14 #include "resolved-dns-transaction.h"
15 #include "resolved-dnstls.h"
16 #include "resolved-llmnr.h"
17 #include "string-table.h"
19 #define TRANSACTIONS_MAX 4096
20 #define TRANSACTION_TCP_TIMEOUT_USEC (10U*USEC_PER_SEC)
22 /* After how much time to repeat classic DNS requests */
23 #define DNS_TIMEOUT_USEC (SD_RESOLVED_QUERY_TIMEOUT_USEC / DNS_TRANSACTION_ATTEMPTS_MAX)
25 static void dns_transaction_reset_answer(DnsTransaction
*t
) {
28 t
->received
= dns_packet_unref(t
->received
);
29 t
->answer
= dns_answer_unref(t
->answer
);
31 t
->answer_ede_rcode
= _DNS_EDE_RCODE_INVALID
;
32 t
->answer_ede_msg
= mfree(t
->answer_ede_msg
);
33 t
->answer_dnssec_result
= _DNSSEC_RESULT_INVALID
;
34 t
->answer_source
= _DNS_TRANSACTION_SOURCE_INVALID
;
35 t
->answer_query_flags
= 0;
36 t
->answer_nsec_ttl
= UINT32_MAX
;
40 static void dns_transaction_flush_dnssec_transactions(DnsTransaction
*t
) {
45 while ((z
= set_steal_first(t
->dnssec_transactions
))) {
46 set_remove(z
->notify_transactions
, t
);
47 set_remove(z
->notify_transactions_done
, t
);
48 dns_transaction_gc(z
);
52 static void dns_transaction_close_connection(
54 bool use_graveyard
) { /* Set use_graveyard = false when you know the connection is already
55 * dead, for example because you got a connection error back from the
56 * kernel. In that case there's no point in keeping the fd around,
63 /* Let's detach the stream from our transaction, in case something else keeps a reference to it. */
64 LIST_REMOVE(transactions_by_stream
, t
->stream
->transactions
, t
);
66 /* Remove packet in case it's still in the queue */
67 dns_packet_unref(ordered_set_remove(t
->stream
->write_queue
, t
->sent
));
69 t
->stream
= dns_stream_unref(t
->stream
);
72 t
->dns_udp_event_source
= sd_event_source_disable_unref(t
->dns_udp_event_source
);
74 /* If we have a UDP socket where we sent a packet, but never received one, then add it to the socket
75 * graveyard, instead of closing it right away. That way it will stick around for a moment longer,
76 * and the reply we might still get from the server will be eaten up instead of resulting in an ICMP
77 * port unreachable error message. */
79 /* Skip the graveyard stuff when we're shutting down, since that requires running event loop.
80 * Note that this is also called from dns_transaction_free(). In that case, scope may be NULL. */
83 !t
->scope
->manager
->event
||
84 sd_event_get_state(t
->scope
->manager
->event
) == SD_EVENT_FINISHED
)
85 use_graveyard
= false;
87 if (use_graveyard
&& t
->dns_udp_fd
>= 0 && t
->sent
&& !t
->received
) {
88 r
= manager_add_socket_to_graveyard(t
->scope
->manager
, t
->dns_udp_fd
);
90 log_debug_errno(r
, "Failed to add UDP socket to graveyard, closing immediately: %m");
92 TAKE_FD(t
->dns_udp_fd
);
95 t
->dns_udp_fd
= safe_close(t
->dns_udp_fd
);
98 static void dns_transaction_stop_timeout(DnsTransaction
*t
) {
101 t
->timeout_event_source
= sd_event_source_disable_unref(t
->timeout_event_source
);
104 DnsTransaction
* dns_transaction_free(DnsTransaction
*t
) {
105 DnsQueryCandidate
*c
;
112 log_debug("Freeing transaction %" PRIu16
".", t
->id
);
114 dns_transaction_close_connection(t
, true);
115 dns_transaction_stop_timeout(t
);
117 dns_packet_unref(t
->sent
);
118 dns_transaction_reset_answer(t
);
120 dns_server_unref(t
->server
);
124 DnsTransaction
*first
;
126 first
= hashmap_get(t
->scope
->transactions_by_key
, t
->key
);
127 LIST_REMOVE(transactions_by_key
, first
, t
);
129 hashmap_replace(t
->scope
->transactions_by_key
, first
->key
, first
);
131 hashmap_remove(t
->scope
->transactions_by_key
, t
->key
);
134 LIST_REMOVE(transactions_by_scope
, t
->scope
->transactions
, t
);
137 hashmap_remove(t
->scope
->manager
->dns_transactions
, UINT_TO_PTR(t
->id
));
140 while ((c
= set_steal_first(t
->notify_query_candidates
)))
141 set_remove(c
->transactions
, t
);
142 set_free(t
->notify_query_candidates
);
144 while ((c
= set_steal_first(t
->notify_query_candidates_done
)))
145 set_remove(c
->transactions
, t
);
146 set_free(t
->notify_query_candidates_done
);
148 while ((i
= set_steal_first(t
->notify_zone_items
)))
149 i
->probe_transaction
= NULL
;
150 set_free(t
->notify_zone_items
);
152 while ((i
= set_steal_first(t
->notify_zone_items_done
)))
153 i
->probe_transaction
= NULL
;
154 set_free(t
->notify_zone_items_done
);
156 while ((z
= set_steal_first(t
->notify_transactions
)))
157 set_remove(z
->dnssec_transactions
, t
);
158 set_free(t
->notify_transactions
);
160 while ((z
= set_steal_first(t
->notify_transactions_done
)))
161 set_remove(z
->dnssec_transactions
, t
);
162 set_free(t
->notify_transactions_done
);
164 dns_transaction_flush_dnssec_transactions(t
);
165 set_free(t
->dnssec_transactions
);
167 dns_answer_unref(t
->validated_keys
);
168 dns_resource_key_unref(t
->key
);
169 dns_packet_unref(t
->bypass
);
174 DEFINE_TRIVIAL_CLEANUP_FUNC(DnsTransaction
*, dns_transaction_free
);
176 DnsTransaction
* dns_transaction_gc(DnsTransaction
*t
) {
179 /* Returns !NULL if we can't gc yet. */
184 if (t
->wait_for_answer
&& IN_SET(t
->state
, DNS_TRANSACTION_PENDING
, DNS_TRANSACTION_VALIDATING
))
187 if (set_isempty(t
->notify_query_candidates
) &&
188 set_isempty(t
->notify_query_candidates_done
) &&
189 set_isempty(t
->notify_zone_items
) &&
190 set_isempty(t
->notify_zone_items_done
) &&
191 set_isempty(t
->notify_transactions
) &&
192 set_isempty(t
->notify_transactions_done
))
193 return dns_transaction_free(t
);
198 static uint16_t pick_new_id(Manager
*m
) {
201 /* Find a fresh, unused transaction id. Note that this loop is bounded because there's a limit on the
202 * number of transactions, and it's much lower than the space of IDs. */
204 assert_cc(TRANSACTIONS_MAX
< 0xFFFF);
207 random_bytes(&new_id
, sizeof(new_id
));
208 while (new_id
== 0 ||
209 hashmap_get(m
->dns_transactions
, UINT_TO_PTR(new_id
)));
216 DnsResourceKey
*key
) {
218 /* Don't allow looking up invalid or pseudo RRs */
219 if (!dns_type_is_valid_query(key
->type
))
221 if (dns_type_is_obsolete(key
->type
))
224 /* We only support the IN class */
225 if (!IN_SET(key
->class, DNS_CLASS_IN
, DNS_CLASS_ANY
))
228 /* Don't allows DNSSEC RRs to be looked up via LLMNR/mDNS. They don't really make sense
229 * there, and it speeds up our queries if we refuse this early */
230 if (scope
->protocol
!= DNS_PROTOCOL_DNS
&&
231 dns_type_is_dnssec(key
->type
))
237 int dns_transaction_new(
238 DnsTransaction
**ret
,
242 uint64_t query_flags
) {
244 _cleanup_(dns_transaction_freep
) DnsTransaction
*t
= NULL
;
260 r
= dns_packet_validate_query(bypass
);
264 DNS_QUESTION_FOREACH(qk
, bypass
->question
) {
271 if (hashmap_size(s
->manager
->dns_transactions
) >= TRANSACTIONS_MAX
)
274 r
= hashmap_ensure_allocated(&s
->manager
->dns_transactions
, NULL
);
279 r
= hashmap_ensure_allocated(&s
->transactions_by_key
, &dns_resource_key_hash_ops
);
284 t
= new(DnsTransaction
, 1);
288 *t
= (DnsTransaction
) {
289 .dns_udp_fd
= -EBADF
,
290 .answer_source
= _DNS_TRANSACTION_SOURCE_INVALID
,
291 .answer_dnssec_result
= _DNSSEC_RESULT_INVALID
,
292 .answer_ede_rcode
= _DNS_EDE_RCODE_INVALID
,
293 .answer_nsec_ttl
= UINT32_MAX
,
294 .key
= dns_resource_key_ref(key
),
295 .query_flags
= query_flags
,
296 .bypass
= dns_packet_ref(bypass
),
297 .current_feature_level
= _DNS_SERVER_FEATURE_LEVEL_INVALID
,
298 .clamp_feature_level_servfail
= _DNS_SERVER_FEATURE_LEVEL_INVALID
,
299 .id
= pick_new_id(s
->manager
),
302 r
= hashmap_put(s
->manager
->dns_transactions
, UINT_TO_PTR(t
->id
), t
);
309 DnsTransaction
*first
;
311 first
= hashmap_get(s
->transactions_by_key
, t
->key
);
312 LIST_PREPEND(transactions_by_key
, first
, t
);
314 r
= hashmap_replace(s
->transactions_by_key
, first
->key
, first
);
316 LIST_REMOVE(transactions_by_key
, first
, t
);
321 LIST_PREPEND(transactions_by_scope
, s
->transactions
, t
);
324 s
->manager
->n_transactions_total
++;
333 static void dns_transaction_shuffle_id(DnsTransaction
*t
) {
337 /* Pick a new ID for this transaction. */
339 new_id
= pick_new_id(t
->scope
->manager
);
340 assert_se(hashmap_remove_and_put(t
->scope
->manager
->dns_transactions
, UINT_TO_PTR(t
->id
), UINT_TO_PTR(new_id
), t
) >= 0);
342 log_debug("Transaction %" PRIu16
" is now %" PRIu16
".", t
->id
, new_id
);
345 /* Make sure we generate a new packet with the new ID */
346 t
->sent
= dns_packet_unref(t
->sent
);
349 static void dns_transaction_tentative(DnsTransaction
*t
, DnsPacket
*p
) {
350 char key_str
[DNS_RESOURCE_KEY_STRING_MAX
];
355 assert(t
->scope
->protocol
== DNS_PROTOCOL_LLMNR
);
357 if (manager_packet_from_local_address(t
->scope
->manager
, p
) != 0)
360 log_debug("Transaction %" PRIu16
" for <%s> on scope %s on %s/%s got tentative packet from %s.",
362 dns_resource_key_to_string(dns_transaction_key(t
), key_str
, sizeof key_str
),
363 dns_protocol_to_string(t
->scope
->protocol
),
364 t
->scope
->link
? t
->scope
->link
->ifname
: "*",
365 af_to_name_short(t
->scope
->family
),
366 IN_ADDR_TO_STRING(p
->family
, &p
->sender
));
368 /* RFC 4795, Section 4.1 says that the peer with the
369 * lexicographically smaller IP address loses */
370 if (memcmp(&p
->sender
, &p
->destination
, FAMILY_ADDRESS_SIZE(p
->family
)) >= 0) {
371 log_debug("Peer has lexicographically larger IP address and thus lost in the conflict.");
375 log_debug("We have the lexicographically larger IP address and thus lost in the conflict.");
379 while ((z
= set_first(t
->notify_zone_items
))) {
380 /* First, make sure the zone item drops the reference
382 dns_zone_item_probe_stop(z
);
384 /* Secondly, report this as conflict, so that we might
385 * look for a different hostname */
386 dns_zone_item_conflict(z
);
390 dns_transaction_gc(t
);
393 void dns_transaction_complete(DnsTransaction
*t
, DnsTransactionState state
) {
394 DnsQueryCandidate
*c
;
398 char key_str
[DNS_RESOURCE_KEY_STRING_MAX
];
401 assert(!DNS_TRANSACTION_IS_LIVE(state
));
403 if (state
== DNS_TRANSACTION_DNSSEC_FAILED
) {
404 dns_resource_key_to_string(dns_transaction_key(t
), key_str
, sizeof key_str
);
406 log_struct(LOG_NOTICE
,
407 "MESSAGE_ID=" SD_MESSAGE_DNSSEC_FAILURE_STR
,
408 LOG_MESSAGE("DNSSEC validation failed for question %s: %s",
409 key_str
, dnssec_result_to_string(t
->answer_dnssec_result
)),
410 "DNS_TRANSACTION=%" PRIu16
, t
->id
,
411 "DNS_QUESTION=%s", key_str
,
412 "DNSSEC_RESULT=%s", dnssec_result_to_string(t
->answer_dnssec_result
),
413 "DNS_SERVER=%s", strna(dns_server_string_full(t
->server
)),
414 "DNS_SERVER_FEATURE_LEVEL=%s", dns_server_feature_level_to_string(t
->server
->possible_feature_level
));
417 /* Note that this call might invalidate the query. Callers
418 * should hence not attempt to access the query or transaction
419 * after calling this function. */
421 if (state
== DNS_TRANSACTION_ERRNO
)
422 st
= errno_to_name(t
->answer_errno
);
424 st
= dns_transaction_state_to_string(state
);
426 log_debug("%s transaction %" PRIu16
" for <%s> on scope %s on %s/%s now complete with <%s> from %s (%s; %s).",
427 t
->bypass
? "Bypass" : "Regular",
429 dns_resource_key_to_string(dns_transaction_key(t
), key_str
, sizeof key_str
),
430 dns_protocol_to_string(t
->scope
->protocol
),
431 t
->scope
->link
? t
->scope
->link
->ifname
: "*",
432 af_to_name_short(t
->scope
->family
),
434 t
->answer_source
< 0 ? "none" : dns_transaction_source_to_string(t
->answer_source
),
435 FLAGS_SET(t
->query_flags
, SD_RESOLVED_NO_VALIDATE
) ? "not validated" :
436 (FLAGS_SET(t
->answer_query_flags
, SD_RESOLVED_AUTHENTICATED
) ? "authenticated" : "unsigned"),
437 FLAGS_SET(t
->answer_query_flags
, SD_RESOLVED_CONFIDENTIAL
) ? "confidential" : "non-confidential");
441 dns_transaction_close_connection(t
, true);
442 dns_transaction_stop_timeout(t
);
444 /* Notify all queries that are interested, but make sure the
445 * transaction isn't freed while we are still looking at it */
448 SET_FOREACH_MOVE(c
, t
->notify_query_candidates_done
, t
->notify_query_candidates
)
449 dns_query_candidate_notify(c
);
450 SWAP_TWO(t
->notify_query_candidates
, t
->notify_query_candidates_done
);
452 SET_FOREACH_MOVE(z
, t
->notify_zone_items_done
, t
->notify_zone_items
)
453 dns_zone_item_notify(z
);
454 SWAP_TWO(t
->notify_zone_items
, t
->notify_zone_items_done
);
455 if (t
->probing
&& t
->state
== DNS_TRANSACTION_ATTEMPTS_MAX_REACHED
)
456 (void) dns_scope_announce(t
->scope
, false);
458 SET_FOREACH_MOVE(d
, t
->notify_transactions_done
, t
->notify_transactions
)
459 dns_transaction_notify(d
, t
);
460 SWAP_TWO(t
->notify_transactions
, t
->notify_transactions_done
);
463 dns_transaction_gc(t
);
466 static void dns_transaction_complete_errno(DnsTransaction
*t
, int error
) {
470 t
->answer_errno
= abs(error
);
471 dns_transaction_complete(t
, DNS_TRANSACTION_ERRNO
);
474 static int dns_transaction_pick_server(DnsTransaction
*t
) {
478 assert(t
->scope
->protocol
== DNS_PROTOCOL_DNS
);
480 /* Pick a DNS server and a feature level for it. */
482 server
= dns_scope_get_dns_server(t
->scope
);
486 /* If we changed the server invalidate the feature level clamping, as the new server might have completely
487 * different properties. */
488 if (server
!= t
->server
)
489 t
->clamp_feature_level_servfail
= _DNS_SERVER_FEATURE_LEVEL_INVALID
;
491 t
->current_feature_level
= dns_server_possible_feature_level(server
);
493 /* Clamp the feature level if that is requested. */
494 if (t
->clamp_feature_level_servfail
!= _DNS_SERVER_FEATURE_LEVEL_INVALID
&&
495 t
->current_feature_level
> t
->clamp_feature_level_servfail
)
496 t
->current_feature_level
= t
->clamp_feature_level_servfail
;
498 log_debug("Using feature level %s for transaction %u.", dns_server_feature_level_to_string(t
->current_feature_level
), t
->id
);
500 if (server
== t
->server
)
503 dns_server_unref(t
->server
);
504 t
->server
= dns_server_ref(server
);
506 t
->n_picked_servers
++;
508 log_debug("Using DNS server %s for transaction %u.", strna(dns_server_string_full(t
->server
)), t
->id
);
513 static void dns_transaction_retry(DnsTransaction
*t
, bool next_server
) {
518 /* Retries the transaction as it is, possibly on a different server */
520 if (next_server
&& t
->scope
->protocol
== DNS_PROTOCOL_DNS
)
521 log_debug("Retrying transaction %" PRIu16
", after switching servers.", t
->id
);
523 log_debug("Retrying transaction %" PRIu16
".", t
->id
);
525 /* Before we try again, switch to a new server. */
527 dns_scope_next_dns_server(t
->scope
, t
->server
);
529 r
= dns_transaction_go(t
);
531 dns_transaction_complete_errno(t
, r
);
534 static bool dns_transaction_limited_retry(DnsTransaction
*t
) {
537 /* If we haven't tried all different servers yet, let's try again with a different server */
539 if (t
->n_picked_servers
>= dns_scope_get_n_dns_servers(t
->scope
))
542 dns_transaction_retry(t
, /* next_server= */ true);
546 static int dns_transaction_maybe_restart(DnsTransaction
*t
) {
551 /* Restarts the transaction, under a new ID if the feature level of the server changed since we first
552 * tried, without changing DNS server. Returns > 0 if the transaction was restarted, 0 if not. */
557 if (t
->current_feature_level
<= dns_server_possible_feature_level(t
->server
))
560 /* The server's current feature level is lower than when we sent the original query. We learnt something from
561 the response or possibly an auxiliary DNSSEC response that we didn't know before. We take that as reason to
562 restart the whole transaction. This is a good idea to deal with servers that respond rubbish if we include
563 OPT RR or DO bit. One of these cases is documented here, for example:
564 https://open.nlnetlabs.nl/pipermail/dnssec-trigger/2014-November/000376.html */
566 log_debug("Server feature level is now lower than when we began our transaction. Restarting with new ID.");
567 dns_transaction_shuffle_id(t
);
569 r
= dns_transaction_go(t
);
576 static void on_transaction_stream_error(DnsTransaction
*t
, int error
) {
579 dns_transaction_close_connection(t
, true);
581 if (ERRNO_IS_DISCONNECT(error
)) {
582 if (t
->scope
->protocol
== DNS_PROTOCOL_LLMNR
) {
583 /* If the LLMNR/TCP connection failed, the host doesn't support LLMNR, and we cannot answer the
584 * question on this scope. */
585 dns_transaction_complete(t
, DNS_TRANSACTION_NOT_FOUND
);
589 dns_transaction_retry(t
, true);
593 dns_transaction_complete_errno(t
, error
);
596 static int dns_transaction_on_stream_packet(DnsTransaction
*t
, DnsStream
*s
, DnsPacket
*p
) {
603 encrypted
= s
->encrypted
;
605 dns_transaction_close_connection(t
, true);
607 if (dns_packet_validate_reply(p
) <= 0) {
608 log_debug("Invalid TCP reply packet.");
609 dns_transaction_complete(t
, DNS_TRANSACTION_INVALID_REPLY
);
613 dns_scope_check_conflicts(t
->scope
, p
);
616 dns_transaction_process_reply(t
, p
, encrypted
);
619 /* If the response wasn't useful, then complete the transition
620 * now. After all, we are the worst feature set now with TCP
621 * sockets, and there's really no point in retrying. */
622 if (t
->state
== DNS_TRANSACTION_PENDING
)
623 dns_transaction_complete(t
, DNS_TRANSACTION_INVALID_REPLY
);
625 dns_transaction_gc(t
);
630 static int on_stream_complete(DnsStream
*s
, int error
) {
633 if (ERRNO_IS_DISCONNECT(error
) && s
->protocol
!= DNS_PROTOCOL_LLMNR
) {
634 log_debug_errno(error
, "Connection failure for DNS TCP stream: %m");
636 if (s
->transactions
) {
640 dns_server_packet_lost(t
->server
, IPPROTO_TCP
, t
->current_feature_level
);
645 /* First, detach the stream from the server. Otherwise, transactions attached to this stream
646 * may be restarted by on_transaction_stream_error() below with this stream. */
647 dns_stream_detach(s
);
649 /* Do not use LIST_FOREACH() here, as
650 * on_transaction_stream_error()
651 * -> dns_transaction_complete_errno()
652 * -> dns_transaction_free()
653 * may free multiple transactions in the list. */
655 while ((t
= s
->transactions
))
656 on_transaction_stream_error(t
, error
);
662 static int on_stream_packet(DnsStream
*s
, DnsPacket
*p
) {
669 t
= hashmap_get(s
->manager
->dns_transactions
, UINT_TO_PTR(DNS_PACKET_ID(p
)));
670 if (t
&& t
->stream
== s
) /* Validate that the stream we got this on actually is the stream the
671 * transaction was using. */
672 return dns_transaction_on_stream_packet(t
, s
, p
);
674 /* Ignore incorrect transaction id as an old transaction can have been canceled. */
675 log_debug("Received unexpected TCP reply packet with id %" PRIu16
", ignoring.", DNS_PACKET_ID(p
));
679 static uint16_t dns_transaction_port(DnsTransaction
*t
) {
682 if (t
->server
->port
> 0)
683 return t
->server
->port
;
685 return DNS_SERVER_FEATURE_LEVEL_IS_TLS(t
->current_feature_level
) ? 853 : 53;
688 static int dns_transaction_emit_tcp(DnsTransaction
*t
) {
689 usec_t stream_timeout_usec
= DNS_STREAM_DEFAULT_TIMEOUT_USEC
;
690 _cleanup_(dns_stream_unrefp
) DnsStream
*s
= NULL
;
691 _cleanup_close_
int fd
= -EBADF
;
692 union sockaddr_union sa
;
699 dns_transaction_close_connection(t
, true);
701 switch (t
->scope
->protocol
) {
703 case DNS_PROTOCOL_DNS
:
704 r
= dns_transaction_pick_server(t
);
708 if (manager_server_is_stub(t
->scope
->manager
, t
->server
))
712 if (!dns_server_dnssec_supported(t
->server
) && dns_type_is_dnssec(dns_transaction_key(t
)->type
))
715 r
= dns_server_adjust_opt(t
->server
, t
->sent
, t
->current_feature_level
);
720 if (t
->server
->stream
&& (DNS_SERVER_FEATURE_LEVEL_IS_TLS(t
->current_feature_level
) == t
->server
->stream
->encrypted
))
721 s
= dns_stream_ref(t
->server
->stream
);
723 fd
= dns_scope_socket_tcp(t
->scope
, AF_UNSPEC
, NULL
, t
->server
, dns_transaction_port(t
), &sa
);
725 /* Lower timeout in DNS-over-TLS opportunistic mode. In environments where DoT is blocked
726 * without ICMP response overly long delays when contacting DoT servers are nasty, in
727 * particular if multiple DNS servers are defined which we try in turn and all are
728 * blocked. Hence, substantially lower the timeout in that case. */
729 if (DNS_SERVER_FEATURE_LEVEL_IS_TLS(t
->current_feature_level
) &&
730 dns_server_get_dns_over_tls_mode(t
->server
) == DNS_OVER_TLS_OPPORTUNISTIC
)
731 stream_timeout_usec
= DNS_STREAM_OPPORTUNISTIC_TLS_TIMEOUT_USEC
;
733 type
= DNS_STREAM_LOOKUP
;
736 case DNS_PROTOCOL_LLMNR
:
737 /* When we already received a reply to this (but it was truncated), send to its sender address */
739 fd
= dns_scope_socket_tcp(t
->scope
, t
->received
->family
, &t
->received
->sender
, NULL
, t
->received
->sender_port
, &sa
);
741 union in_addr_union address
;
742 int family
= AF_UNSPEC
;
744 /* Otherwise, try to talk to the owner of a
745 * the IP address, in case this is a reverse
748 r
= dns_name_address(dns_resource_key_name(dns_transaction_key(t
)), &family
, &address
);
753 if (family
!= t
->scope
->family
)
756 fd
= dns_scope_socket_tcp(t
->scope
, family
, &address
, NULL
, LLMNR_PORT
, &sa
);
759 type
= DNS_STREAM_LLMNR_SEND
;
763 return -EAFNOSUPPORT
;
770 r
= dns_stream_new(t
->scope
->manager
, &s
, type
, t
->scope
->protocol
, fd
, &sa
,
771 on_stream_packet
, on_stream_complete
, stream_timeout_usec
);
777 #if ENABLE_DNS_OVER_TLS
778 if (t
->scope
->protocol
== DNS_PROTOCOL_DNS
&&
779 DNS_SERVER_FEATURE_LEVEL_IS_TLS(t
->current_feature_level
)) {
782 r
= dnstls_stream_connect_tls(s
, t
->server
);
789 dns_server_unref_stream(t
->server
);
790 s
->server
= dns_server_ref(t
->server
);
791 t
->server
->stream
= dns_stream_ref(s
);
794 /* The interface index is difficult to determine if we are
795 * connecting to the local host, hence fill this in right away
796 * instead of determining it from the socket */
797 s
->ifindex
= dns_scope_ifindex(t
->scope
);
800 t
->stream
= TAKE_PTR(s
);
801 LIST_PREPEND(transactions_by_stream
, t
->stream
->transactions
, t
);
803 r
= dns_stream_write_packet(t
->stream
, t
->sent
);
805 dns_transaction_close_connection(t
, /* use_graveyard= */ false);
809 dns_transaction_reset_answer(t
);
811 t
->tried_stream
= true;
816 static void dns_transaction_cache_answer(DnsTransaction
*t
) {
819 /* For mDNS we cache whenever we get the packet, rather than
820 * in each transaction. */
821 if (!IN_SET(t
->scope
->protocol
, DNS_PROTOCOL_DNS
, DNS_PROTOCOL_LLMNR
))
824 /* Caching disabled? */
825 if (t
->scope
->manager
->enable_cache
== DNS_CACHE_MODE_NO
)
828 /* If validation is turned off for this transaction, but DNSSEC is on, then let's not cache this */
829 if (FLAGS_SET(t
->query_flags
, SD_RESOLVED_NO_VALIDATE
) && t
->scope
->dnssec_mode
!= DNSSEC_NO
)
832 /* Packet from localhost? */
833 if (!t
->scope
->manager
->cache_from_localhost
&&
834 in_addr_is_localhost(t
->received
->family
, &t
->received
->sender
) != 0)
837 dns_cache_put(&t
->scope
->cache
,
838 t
->scope
->manager
->enable_cache
,
840 dns_transaction_key(t
),
843 DNS_PACKET_CD(t
->received
) ? t
->received
: NULL
, /* only cache full packets with CD on,
844 * since our use case for caching them
845 * is "bypass" mode which is only
846 * enabled for CD packets. */
847 t
->answer_query_flags
,
848 t
->answer_dnssec_result
,
851 &t
->received
->sender
,
852 t
->scope
->manager
->stale_retention_usec
);
855 static bool dns_transaction_dnssec_is_live(DnsTransaction
*t
) {
860 SET_FOREACH(dt
, t
->dnssec_transactions
)
861 if (DNS_TRANSACTION_IS_LIVE(dt
->state
))
867 static int dns_transaction_dnssec_ready(DnsTransaction
*t
) {
873 /* Checks whether the auxiliary DNSSEC transactions of our transaction have completed, or are still
874 * ongoing. Returns 0, if we aren't ready for the DNSSEC validation, positive if we are. */
876 SET_FOREACH(dt
, t
->dnssec_transactions
) {
880 case DNS_TRANSACTION_NULL
:
881 case DNS_TRANSACTION_PENDING
:
882 case DNS_TRANSACTION_VALIDATING
:
886 case DNS_TRANSACTION_RCODE_FAILURE
:
887 if (!IN_SET(dt
->answer_rcode
, DNS_RCODE_NXDOMAIN
, DNS_RCODE_SERVFAIL
)) {
888 log_debug("Auxiliary DNSSEC RR query failed with rcode=%s.", FORMAT_DNS_RCODE(dt
->answer_rcode
));
892 /* Fall-through: NXDOMAIN/SERVFAIL is good enough for us. This is because some DNS servers
893 * erroneously return NXDOMAIN/SERVFAIL for empty non-terminals (Akamai...) or missing DS
894 * records (Facebook), and we need to handle that nicely, when asking for parent SOA or similar
895 * RRs to make unsigned proofs. */
897 case DNS_TRANSACTION_SUCCESS
:
901 case DNS_TRANSACTION_DNSSEC_FAILED
:
902 /* We handle DNSSEC failures different from other errors, as we care about the DNSSEC
903 * validation result */
905 log_debug("Auxiliary DNSSEC RR query failed validation: %s%s%s%s%s%s",
906 dnssec_result_to_string(dt
->answer_dnssec_result
),
907 dt
->answer_ede_rcode
>= 0 ? " (" : "",
908 dt
->answer_ede_rcode
>= 0 ? FORMAT_DNS_EDE_RCODE(dt
->answer_ede_rcode
) : "",
909 (dt
->answer_ede_rcode
>= 0 && !isempty(dt
->answer_ede_msg
)) ? ": " : "",
910 dt
->answer_ede_rcode
>= 0 ? strempty(dt
->answer_ede_msg
) : "",
911 dt
->answer_ede_rcode
>= 0 ? ")" : "");
913 /* Copy error code over */
914 t
->answer_dnssec_result
= dt
->answer_dnssec_result
;
915 t
->answer_ede_rcode
= dt
->answer_ede_rcode
;
916 r
= free_and_strdup(&t
->answer_ede_msg
, dt
->answer_ede_msg
);
920 /* The answer would normally be replaced by the validated subset, but at this point
921 * we aren't going to bother validating the rest, so just drop it. */
922 t
->answer
= dns_answer_unref(t
->answer
);
924 dns_transaction_complete(t
, DNS_TRANSACTION_DNSSEC_FAILED
);
928 log_debug("Auxiliary DNSSEC RR query failed with %s", dns_transaction_state_to_string(dt
->state
));
933 /* All is ready, we can go and validate */
937 /* Some auxiliary DNSSEC transaction failed for some reason. Maybe we learned something about the
938 * server due to this failure, and the feature level is now different? Let's see and restart the
939 * transaction if so. If not, let's propagate the auxiliary failure.
941 * This is particularly relevant if an auxiliary request figured out that DNSSEC doesn't work, and we
942 * are in permissive DNSSEC mode, and thus should restart things without DNSSEC magic. */
943 r
= dns_transaction_maybe_restart(t
);
947 return 0; /* don't validate just yet, we restarted things */
949 t
->answer_dnssec_result
= DNSSEC_FAILED_AUXILIARY
;
950 dns_transaction_complete(t
, DNS_TRANSACTION_DNSSEC_FAILED
);
954 static void dns_transaction_process_dnssec(DnsTransaction
*t
) {
959 /* Are there ongoing DNSSEC transactions? If so, let's wait for them. */
960 r
= dns_transaction_dnssec_ready(t
);
963 if (r
== 0) /* We aren't ready yet (or one of our auxiliary transactions failed, and we shouldn't validate now */
966 /* See if we learnt things from the additional DNSSEC transactions, that we didn't know before, and better
967 * restart the lookup immediately. */
968 r
= dns_transaction_maybe_restart(t
);
971 if (r
> 0) /* Transaction got restarted... */
974 /* All our auxiliary DNSSEC transactions are complete now. Try
975 * to validate our RRset now. */
976 r
= dns_transaction_validate_dnssec(t
);
978 dns_transaction_complete(t
, DNS_TRANSACTION_INVALID_REPLY
);
984 if (t
->answer_dnssec_result
== DNSSEC_INCOMPATIBLE_SERVER
&&
985 t
->scope
->dnssec_mode
== DNSSEC_YES
) {
987 /* We are not in automatic downgrade mode, and the server is bad. Let's try a different server, maybe
990 if (dns_transaction_limited_retry(t
))
993 /* OK, let's give up, apparently all servers we tried didn't work. */
994 dns_transaction_complete(t
, DNS_TRANSACTION_DNSSEC_FAILED
);
998 if (!IN_SET(t
->answer_dnssec_result
,
999 _DNSSEC_RESULT_INVALID
, /* No DNSSEC validation enabled */
1000 DNSSEC_VALIDATED
, /* Answer is signed and validated successfully */
1001 DNSSEC_UNSIGNED
, /* Answer is right-fully unsigned */
1002 DNSSEC_INCOMPATIBLE_SERVER
)) { /* Server does not do DNSSEC (Yay, we are downgrade attack vulnerable!) */
1003 dns_transaction_complete(t
, DNS_TRANSACTION_DNSSEC_FAILED
);
1007 if (t
->answer_dnssec_result
== DNSSEC_INCOMPATIBLE_SERVER
)
1008 dns_server_warn_downgrade(t
->server
);
1010 dns_transaction_cache_answer(t
);
1012 if (t
->answer_rcode
== DNS_RCODE_SUCCESS
)
1013 dns_transaction_complete(t
, DNS_TRANSACTION_SUCCESS
);
1015 dns_transaction_complete(t
, DNS_TRANSACTION_RCODE_FAILURE
);
1020 dns_transaction_complete_errno(t
, r
);
1023 static int dns_transaction_has_positive_answer(DnsTransaction
*t
, DnsAnswerFlags
*flags
) {
1028 /* Checks whether the answer is positive, i.e. either a direct
1029 * answer to the question, or a CNAME/DNAME for it */
1031 r
= dns_answer_match_key(t
->answer
, dns_transaction_key(t
), flags
);
1035 r
= dns_answer_find_cname_or_dname(t
->answer
, dns_transaction_key(t
), NULL
, flags
);
1042 static int dns_transaction_fix_rcode(DnsTransaction
*t
) {
1047 /* Fix up the RCODE to SUCCESS if we get at least one matching RR in a response. Note that this contradicts the
1048 * DNS RFCs a bit. Specifically, RFC 6604 Section 3 clarifies that the RCODE shall say something about a
1049 * CNAME/DNAME chain element coming after the last chain element contained in the message, and not the first
1050 * one included. However, it also indicates that not all DNS servers implement this correctly. Moreover, when
1051 * using DNSSEC we usually only can prove the first element of a CNAME/DNAME chain anyway, hence let's settle
1052 * on always processing the RCODE as referring to the immediate look-up we do, i.e. the first element of a
1053 * CNAME/DNAME chain. This way, we uniformly handle CNAME/DNAME chains, regardless if the DNS server
1054 * incorrectly implements RCODE, whether DNSSEC is in use, or whether the DNS server only supplied us with an
1055 * incomplete CNAME/DNAME chain.
1057 * Or in other words: if we get at least one positive reply in a message we patch NXDOMAIN to become SUCCESS,
1058 * and then rely on the CNAME chasing logic to figure out that there's actually a CNAME error with a new
1061 if (t
->answer_rcode
!= DNS_RCODE_NXDOMAIN
)
1064 r
= dns_transaction_has_positive_answer(t
, NULL
);
1068 t
->answer_rcode
= DNS_RCODE_SUCCESS
;
1072 void dns_transaction_process_reply(DnsTransaction
*t
, DnsPacket
*p
, bool encrypted
) {
1073 bool retry_with_tcp
= false;
1079 assert(t
->scope
->manager
);
1081 if (t
->state
!= DNS_TRANSACTION_PENDING
)
1084 /* Increment the total failure counter only when it is the first attempt at querying and the upstream
1085 * server returns a failure response code. This ensures a more accurate count of the number of queries
1086 * that received a failure response code, as it doesn't consider retries. */
1088 if (t
->n_attempts
== 1 && !IN_SET(DNS_PACKET_RCODE(p
), DNS_RCODE_SUCCESS
, DNS_RCODE_NXDOMAIN
))
1089 t
->scope
->manager
->n_failure_responses_total
++;
1091 /* Note that this call might invalidate the query. Callers
1092 * should hence not attempt to access the query or transaction
1093 * after calling this function. */
1095 log_debug("Processing incoming packet of size %zu on transaction %" PRIu16
" (rcode=%s).",
1097 t
->id
, FORMAT_DNS_RCODE(DNS_PACKET_RCODE(p
)));
1099 switch (t
->scope
->protocol
) {
1101 case DNS_PROTOCOL_LLMNR
:
1102 /* For LLMNR we will not accept any packets from other interfaces */
1104 if (p
->ifindex
!= dns_scope_ifindex(t
->scope
))
1107 if (p
->family
!= t
->scope
->family
)
1110 /* Tentative packets are not full responses but still
1111 * useful for identifying uniqueness conflicts during
1113 if (DNS_PACKET_LLMNR_T(p
)) {
1114 dns_transaction_tentative(t
, p
);
1120 case DNS_PROTOCOL_MDNS
:
1121 /* For mDNS we will not accept any packets from other interfaces */
1123 if (p
->ifindex
!= dns_scope_ifindex(t
->scope
))
1126 if (p
->family
!= t
->scope
->family
)
1131 case DNS_PROTOCOL_DNS
:
1132 /* Note that we do not need to verify the
1133 * addresses/port numbers of incoming traffic, as we
1134 * invoked connect() on our UDP socket in which case
1135 * the kernel already does the needed verification for
1140 assert_not_reached();
1143 if (t
->received
!= p
)
1144 DNS_PACKET_REPLACE(t
->received
, dns_packet_ref(p
));
1146 t
->answer_source
= DNS_TRANSACTION_NETWORK
;
1148 if (p
->ipproto
== IPPROTO_TCP
) {
1149 if (DNS_PACKET_TC(p
)) {
1150 /* Truncated via TCP? Somebody must be fucking with us */
1151 dns_transaction_complete(t
, DNS_TRANSACTION_INVALID_REPLY
);
1155 if (DNS_PACKET_ID(p
) != t
->id
) {
1156 /* Not the reply to our query? Somebody must be fucking with us */
1157 dns_transaction_complete(t
, DNS_TRANSACTION_INVALID_REPLY
);
1162 if (DNS_PACKET_TC(p
)) {
1164 /* Truncated packets for mDNS are not allowed. Give up immediately. */
1165 if (t
->scope
->protocol
== DNS_PROTOCOL_MDNS
) {
1166 dns_transaction_complete(t
, DNS_TRANSACTION_INVALID_REPLY
);
1170 /* Response was truncated, let's try again with good old TCP */
1171 log_debug("Reply truncated, retrying via TCP.");
1172 retry_with_tcp
= true;
1174 } else if (t
->scope
->protocol
== DNS_PROTOCOL_DNS
&&
1175 DNS_PACKET_IS_FRAGMENTED(p
)) {
1177 /* Report the fragment size, so that we downgrade from LARGE to regular EDNS0 if needed */
1179 dns_server_packet_udp_fragmented(t
->server
, dns_packet_size_unfragmented(p
));
1181 if (t
->current_feature_level
> DNS_SERVER_FEATURE_LEVEL_UDP
) {
1182 /* Packet was fragmented. Let's retry with TCP to avoid fragmentation attack
1183 * issues. (We don't do that on the lowest feature level however, since crappy DNS
1184 * servers often do not implement TCP, hence falling back to TCP on fragmentation is
1185 * counter-productive there.) */
1187 log_debug("Reply fragmented, retrying via TCP. (Largest fragment size: %zu; Datagram size: %zu)",
1188 p
->fragsize
, p
->size
);
1189 retry_with_tcp
= true;
1193 if (retry_with_tcp
) {
1194 r
= dns_transaction_emit_tcp(t
);
1196 /* No servers found? Damn! */
1197 dns_transaction_complete(t
, DNS_TRANSACTION_NO_SERVERS
);
1200 if (r
== -EOPNOTSUPP
) {
1201 /* Tried to ask for DNSSEC RRs, on a server that doesn't do DNSSEC */
1202 dns_transaction_complete(t
, DNS_TRANSACTION_RR_TYPE_UNSUPPORTED
);
1206 /* On LLMNR, if we cannot connect to the host,
1207 * we immediately give up */
1208 if (t
->scope
->protocol
!= DNS_PROTOCOL_DNS
)
1211 /* On DNS, couldn't send? Try immediately again, with a new server */
1212 if (dns_transaction_limited_retry(t
))
1215 /* No new server to try, give up */
1216 dns_transaction_complete(t
, DNS_TRANSACTION_ATTEMPTS_MAX_REACHED
);
1222 /* After the superficial checks, actually parse the message. */
1223 r
= dns_packet_extract(p
);
1226 dns_server_packet_invalid(t
->server
, t
->current_feature_level
);
1228 r
= dns_transaction_maybe_restart(t
);
1231 if (r
> 0) /* Transaction got restarted... */
1235 dns_transaction_complete(t
, DNS_TRANSACTION_INVALID_REPLY
);
1239 switch (t
->scope
->protocol
) {
1241 case DNS_PROTOCOL_DNS
: {
1244 (void) dns_packet_ede_rcode(p
, &t
->answer_ede_rcode
, &t
->answer_ede_msg
);
1247 IN_SET(DNS_PACKET_RCODE(p
), DNS_RCODE_FORMERR
, DNS_RCODE_SERVFAIL
, DNS_RCODE_NOTIMP
)) {
1248 /* If the server has replied with detailed error data, using a degraded feature set
1249 * will likely not help anyone. Examine the detailed error to determine the best
1250 * course of action. */
1251 if (t
->answer_ede_rcode
>= 0 && DNS_PACKET_RCODE(p
) == DNS_RCODE_SERVFAIL
) {
1252 /* These codes are related to DNSSEC configuration errors. If accurate,
1253 * this is the domain operator's problem, and retrying won't help. */
1254 if (dns_ede_rcode_is_dnssec(t
->answer_ede_rcode
)) {
1255 log_debug("Server returned error: %s (%s%s%s). Lookup failed.",
1256 FORMAT_DNS_RCODE(DNS_PACKET_RCODE(p
)),
1257 FORMAT_DNS_EDE_RCODE(t
->answer_ede_rcode
),
1258 isempty(t
->answer_ede_msg
) ? "" : ": ",
1259 strempty(t
->answer_ede_msg
));
1261 t
->answer_dnssec_result
= DNSSEC_UPSTREAM_FAILURE
;
1262 dns_transaction_complete(t
, DNS_TRANSACTION_DNSSEC_FAILED
);
1266 /* These codes probably indicate a transient error. Let's try again. */
1267 if (IN_SET(t
->answer_ede_rcode
, DNS_EDE_RCODE_NOT_READY
, DNS_EDE_RCODE_NET_ERROR
)) {
1268 log_debug("Server returned error: %s (%s%s%s), retrying transaction.",
1269 FORMAT_DNS_RCODE(DNS_PACKET_RCODE(p
)),
1270 FORMAT_DNS_EDE_RCODE(t
->answer_ede_rcode
),
1271 isempty(t
->answer_ede_msg
) ? "" : ": ",
1272 strempty(t
->answer_ede_msg
));
1273 dns_transaction_retry(t
, false);
1277 /* OK, the query failed, but we still shouldn't degrade the feature set for
1279 log_debug("Server returned error: %s (%s%s%s)",
1280 FORMAT_DNS_RCODE(DNS_PACKET_RCODE(p
)),
1281 FORMAT_DNS_EDE_RCODE(t
->answer_ede_rcode
),
1282 isempty(t
->answer_ede_msg
) ? "" : ": ",
1283 strempty(t
->answer_ede_msg
));
1287 /* Request failed, immediately try again with reduced features */
1289 if (t
->current_feature_level
<= DNS_SERVER_FEATURE_LEVEL_UDP
) {
1291 /* This was already at UDP feature level? If so, it doesn't make sense to downgrade
1292 * this transaction anymore, but let's see if it might make sense to send the request
1293 * to a different DNS server instead. If not let's process the response, and accept the
1294 * rcode. Note that we don't retry on TCP, since that's a suitable way to mitigate
1295 * packet loss, but is not going to give us better rcodes should we actually have
1296 * managed to get them already at UDP level. */
1298 if (dns_transaction_limited_retry(t
))
1301 /* Give up, accept the rcode */
1302 log_debug("Server returned error: %s", FORMAT_DNS_RCODE(DNS_PACKET_RCODE(p
)));
1306 /* SERVFAIL can happen for many reasons and may be transient.
1307 * To avoid unnecessary downgrades retry once with the initial level.
1308 * Check for clamp_feature_level_servfail having an invalid value as a sign that this is the
1309 * first attempt to downgrade. If so, clamp to the current value so that the transaction
1310 * is retried without actually downgrading. If the next try also fails we will downgrade by
1311 * hitting the else branch below. */
1312 if (DNS_PACKET_RCODE(p
) == DNS_RCODE_SERVFAIL
&&
1313 t
->clamp_feature_level_servfail
< 0) {
1314 t
->clamp_feature_level_servfail
= t
->current_feature_level
;
1315 log_debug("Server returned error %s, retrying transaction.",
1316 FORMAT_DNS_RCODE(DNS_PACKET_RCODE(p
)));
1318 /* Reduce this feature level by one and try again. */
1319 switch (t
->current_feature_level
) {
1320 case DNS_SERVER_FEATURE_LEVEL_TLS_DO
:
1321 t
->clamp_feature_level_servfail
= DNS_SERVER_FEATURE_LEVEL_TLS_PLAIN
;
1323 case DNS_SERVER_FEATURE_LEVEL_TLS_PLAIN
+ 1:
1324 /* Skip plain TLS when TLS is not supported */
1325 t
->clamp_feature_level_servfail
= DNS_SERVER_FEATURE_LEVEL_TLS_PLAIN
- 1;
1328 t
->clamp_feature_level_servfail
= t
->current_feature_level
- 1;
1331 log_debug("Server returned error %s, retrying transaction with reduced feature level %s.",
1332 FORMAT_DNS_RCODE(DNS_PACKET_RCODE(p
)),
1333 dns_server_feature_level_to_string(t
->clamp_feature_level_servfail
));
1336 dns_transaction_retry(t
, false /* use the same server */);
1340 if (DNS_PACKET_RCODE(p
) == DNS_RCODE_REFUSED
) {
1341 /* This server refused our request? If so, try again, use a different server */
1342 if (t
->answer_ede_rcode
>= 0)
1343 log_debug("Server returned REFUSED (%s), switching servers, and retrying.",
1344 FORMAT_DNS_EDE_RCODE(t
->answer_ede_rcode
));
1346 log_debug("Server returned REFUSED, switching servers, and retrying.");
1348 if (dns_transaction_limited_retry(t
))
1354 if (DNS_PACKET_TC(p
))
1355 dns_server_packet_truncated(t
->server
, t
->current_feature_level
);
1360 case DNS_PROTOCOL_LLMNR
:
1361 case DNS_PROTOCOL_MDNS
:
1362 dns_scope_packet_received(t
->scope
, p
->timestamp
- t
->start_usec
);
1366 assert_not_reached();
1370 /* Report that we successfully received a valid packet with a good rcode after we initially got a bad
1371 * rcode and subsequently downgraded the protocol */
1373 if (IN_SET(DNS_PACKET_RCODE(p
), DNS_RCODE_SUCCESS
, DNS_RCODE_NXDOMAIN
) &&
1374 t
->clamp_feature_level_servfail
!= _DNS_SERVER_FEATURE_LEVEL_INVALID
)
1375 dns_server_packet_rcode_downgrade(t
->server
, t
->clamp_feature_level_servfail
);
1377 /* Report that the OPT RR was missing */
1379 dns_server_packet_bad_opt(t
->server
, t
->current_feature_level
);
1381 /* Report that the server didn't copy our query DO bit from request to response */
1382 if (DNS_PACKET_DO(t
->sent
) && !DNS_PACKET_DO(t
->received
))
1383 dns_server_packet_do_off(t
->server
, t
->current_feature_level
);
1385 /* Report that we successfully received a packet. We keep track of the largest packet
1386 * size/fragment size we got. Which is useful for announcing the EDNS(0) packet size we can
1387 * receive to our server. */
1388 dns_server_packet_received(t
->server
, p
->ipproto
, t
->current_feature_level
, dns_packet_size_unfragmented(p
));
1391 /* See if we know things we didn't know before that indicate we better restart the lookup immediately. */
1392 r
= dns_transaction_maybe_restart(t
);
1395 if (r
> 0) /* Transaction got restarted... */
1398 /* When dealing with protocols other than mDNS only consider responses with equivalent query section
1399 * to the request. For mDNS this check doesn't make sense, because the section 6 of RFC6762 states
1400 * that "Multicast DNS responses MUST NOT contain any questions in the Question Section". */
1401 if (t
->scope
->protocol
!= DNS_PROTOCOL_MDNS
) {
1402 r
= dns_packet_is_reply_for(p
, dns_transaction_key(t
));
1406 dns_transaction_complete(t
, DNS_TRANSACTION_INVALID_REPLY
);
1411 /* Install the answer as answer to the transaction. We ref the answer twice here: the main `answer`
1412 * field is later replaced by the DNSSEC validated subset. The 'answer_auxiliary' field carries the
1413 * original complete record set, including RRSIG and friends. We use this when passing data to
1414 * clients that ask for DNSSEC metadata. */
1415 DNS_ANSWER_REPLACE(t
->answer
, dns_answer_ref(p
->answer
));
1416 t
->answer_rcode
= DNS_PACKET_RCODE(p
);
1417 t
->answer_dnssec_result
= _DNSSEC_RESULT_INVALID
;
1418 SET_FLAG(t
->answer_query_flags
, SD_RESOLVED_AUTHENTICATED
, false);
1419 SET_FLAG(t
->answer_query_flags
, SD_RESOLVED_CONFIDENTIAL
, encrypted
);
1421 r
= dns_transaction_fix_rcode(t
);
1425 /* Block GC while starting requests for additional DNSSEC RRs */
1427 r
= dns_transaction_request_dnssec_keys(t
);
1430 /* Maybe the transaction is ready for GC'ing now? If so, free it and return. */
1431 if (!dns_transaction_gc(t
))
1434 /* Requesting additional keys might have resulted in this transaction to fail, since the auxiliary
1435 * request failed for some reason. If so, we are not in pending state anymore, and we should exit
1437 if (t
->state
!= DNS_TRANSACTION_PENDING
)
1442 /* There are DNSSEC transactions pending now. Update the state accordingly. */
1443 t
->state
= DNS_TRANSACTION_VALIDATING
;
1444 dns_transaction_close_connection(t
, true);
1445 dns_transaction_stop_timeout(t
);
1449 dns_transaction_process_dnssec(t
);
1453 dns_transaction_complete_errno(t
, r
);
1456 static int on_dns_packet(sd_event_source
*s
, int fd
, uint32_t revents
, void *userdata
) {
1457 _cleanup_(dns_packet_unrefp
) DnsPacket
*p
= NULL
;
1458 DnsTransaction
*t
= ASSERT_PTR(userdata
);
1463 r
= manager_recv(t
->scope
->manager
, fd
, DNS_PROTOCOL_DNS
, &p
);
1465 if (ERRNO_IS_DISCONNECT(r
)) {
1468 /* UDP connection failures get reported via ICMP and then are possibly delivered to us on the
1469 * next recvmsg(). Treat this like a lost packet. */
1471 log_debug_errno(r
, "Connection failure for DNS UDP packet: %m");
1472 assert_se(sd_event_now(t
->scope
->manager
->event
, CLOCK_BOOTTIME
, &usec
) >= 0);
1473 dns_server_packet_lost(t
->server
, IPPROTO_UDP
, t
->current_feature_level
);
1475 dns_transaction_close_connection(t
, /* use_graveyard = */ false);
1477 if (dns_transaction_limited_retry(t
)) /* Try a different server */
1480 dns_transaction_complete_errno(t
, r
);
1484 /* Spurious wakeup without any data */
1487 r
= dns_packet_validate_reply(p
);
1489 log_debug_errno(r
, "Received invalid DNS packet as response, ignoring: %m");
1493 log_debug("Received inappropriate DNS packet as response, ignoring.");
1497 if (DNS_PACKET_ID(p
) != t
->id
) {
1498 log_debug("Received packet with incorrect transaction ID, ignoring.");
1502 dns_transaction_process_reply(t
, p
, false);
1506 static int dns_transaction_emit_udp(DnsTransaction
*t
) {
1511 if (t
->scope
->protocol
== DNS_PROTOCOL_DNS
) {
1513 r
= dns_transaction_pick_server(t
);
1517 if (manager_server_is_stub(t
->scope
->manager
, t
->server
))
1520 if (t
->current_feature_level
< DNS_SERVER_FEATURE_LEVEL_UDP
|| DNS_SERVER_FEATURE_LEVEL_IS_TLS(t
->current_feature_level
))
1521 return -EAGAIN
; /* Sorry, can't do UDP, try TCP! */
1523 if (!t
->bypass
&& !dns_server_dnssec_supported(t
->server
) && dns_type_is_dnssec(dns_transaction_key(t
)->type
))
1526 if (r
> 0 || t
->dns_udp_fd
< 0) { /* Server changed, or no connection yet. */
1529 dns_transaction_close_connection(t
, true);
1531 /* Before we allocate a new UDP socket, let's process the graveyard a bit to free some fds */
1532 manager_socket_graveyard_process(t
->scope
->manager
);
1534 fd
= dns_scope_socket_udp(t
->scope
, t
->server
);
1538 r
= sd_event_add_io(t
->scope
->manager
->event
, &t
->dns_udp_event_source
, fd
, EPOLLIN
, on_dns_packet
, t
);
1544 (void) sd_event_source_set_description(t
->dns_udp_event_source
, "dns-transaction-udp");
1549 r
= dns_server_adjust_opt(t
->server
, t
->sent
, t
->current_feature_level
);
1554 dns_transaction_close_connection(t
, true);
1556 r
= dns_scope_emit_udp(t
->scope
, t
->dns_udp_fd
, t
->server
? t
->server
->family
: AF_UNSPEC
, t
->sent
);
1560 dns_transaction_reset_answer(t
);
1565 static int on_transaction_timeout(sd_event_source
*s
, usec_t usec
, void *userdata
) {
1566 DnsTransaction
*t
= ASSERT_PTR(userdata
);
1570 t
->seen_timeout
= true;
1572 if (t
->initial_jitter_scheduled
&& !t
->initial_jitter_elapsed
) {
1573 log_debug("Initial jitter phase for transaction %" PRIu16
" elapsed.", t
->id
);
1574 t
->initial_jitter_elapsed
= true;
1576 /* Timeout reached? Increase the timeout for the server used */
1577 switch (t
->scope
->protocol
) {
1579 case DNS_PROTOCOL_DNS
:
1581 dns_server_packet_lost(t
->server
, t
->stream
? IPPROTO_TCP
: IPPROTO_UDP
, t
->current_feature_level
);
1584 case DNS_PROTOCOL_LLMNR
:
1585 case DNS_PROTOCOL_MDNS
:
1586 dns_scope_packet_lost(t
->scope
, usec
- t
->start_usec
);
1590 assert_not_reached();
1593 log_debug("Timeout reached on transaction %" PRIu16
".", t
->id
);
1596 dns_transaction_retry(t
, /* next_server= */ true); /* try a different server, but given this means
1597 * packet loss, let's do so even if we already
1602 static int dns_transaction_setup_timeout(
1604 usec_t timeout_usec
/* relative */,
1605 usec_t next_usec
/* CLOCK_BOOTTIME */) {
1611 dns_transaction_stop_timeout(t
);
1613 r
= sd_event_add_time_relative(
1614 t
->scope
->manager
->event
,
1615 &t
->timeout_event_source
,
1618 on_transaction_timeout
, t
);
1622 (void) sd_event_source_set_description(t
->timeout_event_source
, "dns-transaction-timeout");
1624 t
->next_attempt_after
= next_usec
;
1625 t
->state
= DNS_TRANSACTION_PENDING
;
1629 static usec_t
transaction_get_resend_timeout(DnsTransaction
*t
) {
1633 switch (t
->scope
->protocol
) {
1635 case DNS_PROTOCOL_DNS
:
1637 /* When we do TCP, grant a much longer timeout, as in this case there's no need for us to quickly
1638 * resend, as the kernel does that anyway for us, and we really don't want to interrupt it in that
1641 return TRANSACTION_TCP_TIMEOUT_USEC
;
1643 return DNS_TIMEOUT_USEC
;
1645 case DNS_PROTOCOL_MDNS
:
1647 return MDNS_PROBING_INTERVAL_USEC
;
1649 /* See RFC 6762 Section 5.1 suggests that timeout should be a few seconds. */
1650 assert(t
->n_attempts
> 0);
1651 return (1 << (t
->n_attempts
- 1)) * USEC_PER_SEC
;
1653 case DNS_PROTOCOL_LLMNR
:
1654 return t
->scope
->resend_timeout
;
1657 assert_not_reached();
1661 static void dns_transaction_randomize_answer(DnsTransaction
*t
) {
1666 /* Randomizes the order of the answer array. This is done for all cached responses, so that we return
1667 * a different order each time. We do this only for DNS traffic, in order to do some minimal, crappy
1668 * load balancing. We don't do this for LLMNR or mDNS, since the order (preferring link-local
1669 * addresses, and such like) might have meaning there, and load balancing is pointless. */
1671 if (t
->scope
->protocol
!= DNS_PROTOCOL_DNS
)
1674 /* No point in randomizing, if there's just one RR */
1675 if (dns_answer_size(t
->answer
) <= 1)
1678 r
= dns_answer_reserve_or_clone(&t
->answer
, 0);
1679 if (r
< 0) /* If this fails, just don't randomize, this is non-essential stuff after all */
1680 return (void) log_debug_errno(r
, "Failed to clone answer record, not randomizing RR order of answer: %m");
1682 dns_answer_randomize(t
->answer
);
1685 static int dns_transaction_prepare(DnsTransaction
*t
, usec_t ts
) {
1690 /* Returns 0 if dns_transaction_complete() has been called. In that case the transaction and query
1691 * candidate objects may have been invalidated and must not be accessed. Returns 1 if the transaction
1692 * has been prepared. */
1694 dns_transaction_stop_timeout(t
);
1696 if (t
->n_attempts
== 1 && t
->seen_timeout
)
1697 t
->scope
->manager
->n_timeouts_total
++;
1699 if (!dns_scope_network_good(t
->scope
)) {
1700 dns_transaction_complete(t
, DNS_TRANSACTION_NETWORK_DOWN
);
1704 if (t
->n_attempts
>= TRANSACTION_ATTEMPTS_MAX(t
->scope
->protocol
)) {
1705 DnsTransactionState result
;
1707 if (t
->scope
->protocol
== DNS_PROTOCOL_LLMNR
)
1708 /* If we didn't find anything on LLMNR, it's not an error, but a failure to resolve
1710 result
= DNS_TRANSACTION_NOT_FOUND
;
1712 result
= DNS_TRANSACTION_ATTEMPTS_MAX_REACHED
;
1714 dns_transaction_complete(t
, result
);
1718 if (t
->scope
->protocol
== DNS_PROTOCOL_LLMNR
&& t
->tried_stream
) {
1719 /* If we already tried via a stream, then we don't
1720 * retry on LLMNR. See RFC 4795, Section 2.7. */
1721 dns_transaction_complete(t
, DNS_TRANSACTION_ATTEMPTS_MAX_REACHED
);
1728 dns_transaction_reset_answer(t
);
1729 dns_transaction_flush_dnssec_transactions(t
);
1731 /* Check the trust anchor. Do so only on classic DNS, since DNSSEC does not apply otherwise. */
1732 if (t
->scope
->protocol
== DNS_PROTOCOL_DNS
&&
1733 !FLAGS_SET(t
->query_flags
, SD_RESOLVED_NO_TRUST_ANCHOR
)) {
1734 r
= dns_trust_anchor_lookup_positive(&t
->scope
->manager
->trust_anchor
, dns_transaction_key(t
), &t
->answer
);
1738 t
->answer_rcode
= DNS_RCODE_SUCCESS
;
1739 t
->answer_source
= DNS_TRANSACTION_TRUST_ANCHOR
;
1740 SET_FLAG(t
->answer_query_flags
, SD_RESOLVED_AUTHENTICATED
|SD_RESOLVED_CONFIDENTIAL
, true);
1741 dns_transaction_complete(t
, DNS_TRANSACTION_SUCCESS
);
1745 if (dns_name_is_root(dns_resource_key_name(dns_transaction_key(t
))) &&
1746 dns_transaction_key(t
)->type
== DNS_TYPE_DS
) {
1748 /* Hmm, this is a request for the root DS? A DS RR doesn't exist in the root zone,
1749 * and if our trust anchor didn't know it either, this means we cannot do any DNSSEC
1752 if (t
->scope
->dnssec_mode
== DNSSEC_ALLOW_DOWNGRADE
) {
1753 /* We are in downgrade mode. In this case, synthesize an unsigned empty
1754 * response, so that the any lookup depending on this one can continue
1755 * assuming there was no DS, and hence the root zone was unsigned. */
1757 t
->answer_rcode
= DNS_RCODE_SUCCESS
;
1758 t
->answer_source
= DNS_TRANSACTION_TRUST_ANCHOR
;
1759 SET_FLAG(t
->answer_query_flags
, SD_RESOLVED_AUTHENTICATED
, false);
1760 SET_FLAG(t
->answer_query_flags
, SD_RESOLVED_CONFIDENTIAL
, true);
1761 dns_transaction_complete(t
, DNS_TRANSACTION_SUCCESS
);
1763 /* If we are not in downgrade mode, then fail the lookup, because we cannot
1764 * reasonably answer it. There might be DS RRs, but we don't know them, and
1765 * the DNS server won't tell them to us (and even if it would, we couldn't
1766 * validate and trust them. */
1767 dns_transaction_complete(t
, DNS_TRANSACTION_NO_TRUST_ANCHOR
);
1773 /* Check the zone. */
1774 if (!FLAGS_SET(t
->query_flags
, SD_RESOLVED_NO_ZONE
)) {
1775 r
= dns_zone_lookup(&t
->scope
->zone
, dns_transaction_key(t
), dns_scope_ifindex(t
->scope
), &t
->answer
, NULL
, NULL
);
1779 t
->answer_rcode
= DNS_RCODE_SUCCESS
;
1780 t
->answer_source
= DNS_TRANSACTION_ZONE
;
1781 SET_FLAG(t
->answer_query_flags
, SD_RESOLVED_AUTHENTICATED
|SD_RESOLVED_CONFIDENTIAL
, true);
1782 dns_transaction_complete(t
, DNS_TRANSACTION_SUCCESS
);
1787 /* Check the cache. */
1788 if (!FLAGS_SET(t
->query_flags
, SD_RESOLVED_NO_CACHE
)) {
1790 /* Before trying the cache, let's make sure we figured out a server to use. Should this cause
1791 * a change of server this might flush the cache. */
1792 (void) dns_scope_get_dns_server(t
->scope
);
1794 /* Let's then prune all outdated entries */
1795 dns_cache_prune(&t
->scope
->cache
);
1797 /* For the initial attempt or when no stale data is requested, disable serve stale
1798 * and answer the question from the cache (honors ttl property).
1799 * On the second attempt, if StaleRetentionSec is greater than zero,
1800 * try to answer the question using stale date (honors until property) */
1801 uint64_t query_flags
= t
->query_flags
;
1802 if (t
->n_attempts
== 1 || t
->scope
->manager
->stale_retention_usec
== 0)
1803 query_flags
|= SD_RESOLVED_NO_STALE
;
1805 r
= dns_cache_lookup(
1807 dns_transaction_key(t
),
1812 &t
->answer_query_flags
,
1813 &t
->answer_dnssec_result
);
1817 dns_transaction_randomize_answer(t
);
1819 if (t
->bypass
&& t
->scope
->protocol
== DNS_PROTOCOL_DNS
&& !t
->received
)
1820 /* When bypass mode is on, do not use cached data unless it came with a full
1822 dns_transaction_reset_answer(t
);
1824 if (t
->n_attempts
> 1 && !FLAGS_SET(query_flags
, SD_RESOLVED_NO_STALE
)) {
1826 if (t
->answer_rcode
== DNS_RCODE_SUCCESS
) {
1827 if (t
->seen_timeout
)
1828 t
->scope
->manager
->n_timeouts_served_stale_total
++;
1830 t
->scope
->manager
->n_failure_responses_served_stale_total
++;
1833 char key_str
[DNS_RESOURCE_KEY_STRING_MAX
];
1834 log_debug("Serve Stale response rcode=%s for %s",
1835 FORMAT_DNS_RCODE(t
->answer_rcode
),
1836 dns_resource_key_to_string(dns_transaction_key(t
), key_str
, sizeof key_str
));
1839 t
->answer_source
= DNS_TRANSACTION_CACHE
;
1840 if (t
->answer_rcode
== DNS_RCODE_SUCCESS
)
1841 dns_transaction_complete(t
, DNS_TRANSACTION_SUCCESS
);
1844 (void) dns_packet_ede_rcode(t
->received
, &t
->answer_ede_rcode
, &t
->answer_ede_msg
);
1846 dns_transaction_complete(t
, DNS_TRANSACTION_RCODE_FAILURE
);
1853 if (FLAGS_SET(t
->query_flags
, SD_RESOLVED_NO_NETWORK
)) {
1854 dns_transaction_complete(t
, DNS_TRANSACTION_NO_SOURCE
);
1861 static int dns_packet_append_zone(DnsPacket
*p
, DnsTransaction
*t
, DnsResourceKey
*k
, unsigned *nscount
) {
1862 _cleanup_(dns_answer_unrefp
) DnsAnswer
*answer
= NULL
;
1870 if (k
->type
!= DNS_TYPE_ANY
)
1873 r
= dns_zone_lookup(&t
->scope
->zone
, k
, t
->scope
->link
->ifindex
, &answer
, NULL
, &tentative
);
1877 return dns_packet_append_answer(p
, answer
, nscount
);
1880 static int mdns_make_dummy_packet(DnsTransaction
*t
, DnsPacket
**ret_packet
, Set
**ret_keys
) {
1881 _cleanup_(dns_packet_unrefp
) DnsPacket
*p
= NULL
;
1882 _cleanup_set_free_ Set
*keys
= NULL
;
1883 bool add_known_answers
= false;
1890 assert(t
->scope
->protocol
== DNS_PROTOCOL_MDNS
);
1894 r
= dns_packet_new_query(&p
, t
->scope
->protocol
, 0, false);
1898 r
= dns_packet_append_key(p
, dns_transaction_key(t
), 0, NULL
);
1904 if (dns_key_is_shared(dns_transaction_key(t
)))
1905 add_known_answers
= true;
1907 r
= dns_packet_append_zone(p
, t
, dns_transaction_key(t
), NULL
);
1911 /* Save appended keys */
1912 r
= set_ensure_put(&keys
, &dns_resource_key_hash_ops
, dns_transaction_key(t
));
1916 assert_se(sd_event_now(t
->scope
->manager
->event
, CLOCK_BOOTTIME
, &ts
) >= 0);
1918 LIST_FOREACH(transactions_by_scope
, other
, t
->scope
->transactions
) {
1920 /* Skip ourselves */
1924 if (other
->state
!= DNS_TRANSACTION_PENDING
)
1927 if (other
->next_attempt_after
> ts
)
1930 if (!set_contains(keys
, dns_transaction_key(other
))) {
1931 size_t saved_packet_size
;
1933 r
= dns_packet_append_key(p
, dns_transaction_key(other
), 0, &saved_packet_size
);
1934 /* If we can't stuff more questions into the packet, just give up.
1935 * One of the 'other' transactions will fire later and take care of the rest. */
1941 r
= dns_packet_append_zone(p
, t
, dns_transaction_key(other
), NULL
);
1942 if (r
== -EMSGSIZE
) {
1943 dns_packet_truncate(p
, saved_packet_size
);
1949 r
= set_ensure_put(&keys
, &dns_resource_key_hash_ops
, dns_transaction_key(other
));
1954 r
= dns_transaction_prepare(other
, ts
);
1958 /* In this case, not only this transaction, but multiple transactions may be
1959 * freed. Hence, we need to restart the loop. */
1962 usec_t timeout
= transaction_get_resend_timeout(other
);
1963 r
= dns_transaction_setup_timeout(other
, timeout
, usec_add(ts
, timeout
));
1967 if (dns_key_is_shared(dns_transaction_key(other
)))
1968 add_known_answers
= true;
1971 if (qdcount
>= UINT16_MAX
)
1975 DNS_PACKET_HEADER(p
)->qdcount
= htobe16(qdcount
);
1977 /* Append known answers section if we're asking for any shared record */
1978 if (add_known_answers
) {
1979 r
= dns_cache_export_shared_to_packet(&t
->scope
->cache
, p
, ts
, 0);
1984 *ret_packet
= TAKE_PTR(p
);
1985 *ret_keys
= TAKE_PTR(keys
);
1986 return add_known_answers
;
1989 static int dns_transaction_make_packet_mdns(DnsTransaction
*t
) {
1990 _cleanup_(dns_packet_unrefp
) DnsPacket
*p
= NULL
, *dummy
= NULL
;
1991 _cleanup_set_free_ Set
*keys
= NULL
;
1992 bool add_known_answers
;
1998 assert(t
->scope
->protocol
== DNS_PROTOCOL_MDNS
);
2000 /* Discard any previously prepared packet, so we can start over and coalesce again */
2001 t
->sent
= dns_packet_unref(t
->sent
);
2003 /* First, create a dummy packet to calculate the number of known answers to be appended in the first packet. */
2005 r
= mdns_make_dummy_packet(t
, &dummy
, &keys
);
2011 add_known_answers
= r
;
2015 /* Then, create actual packet. */
2016 r
= dns_packet_new_query(&p
, t
->scope
->protocol
, 0, false);
2022 SET_FOREACH(k
, keys
) {
2023 r
= dns_packet_append_key(p
, k
, 0, NULL
);
2028 DNS_PACKET_HEADER(p
)->qdcount
= htobe16(c
);
2031 if (add_known_answers
) {
2034 assert_se(sd_event_now(t
->scope
->manager
->event
, CLOCK_BOOTTIME
, &ts
) >= 0);
2036 r
= dns_cache_export_shared_to_packet(&t
->scope
->cache
, p
, ts
, be16toh(DNS_PACKET_HEADER(dummy
)->ancount
));
2043 SET_FOREACH(k
, keys
) {
2044 r
= dns_packet_append_zone(p
, t
, k
, &c
);
2048 DNS_PACKET_HEADER(p
)->nscount
= htobe16(c
);
2050 t
->sent
= TAKE_PTR(p
);
2054 static int dns_transaction_make_packet(DnsTransaction
*t
) {
2055 _cleanup_(dns_packet_unrefp
) DnsPacket
*p
= NULL
;
2060 if (t
->scope
->protocol
== DNS_PROTOCOL_MDNS
)
2061 return dns_transaction_make_packet_mdns(t
);
2066 if (t
->bypass
&& t
->bypass
->protocol
== t
->scope
->protocol
) {
2067 /* If bypass logic is enabled and the protocol if the original packet and our scope match,
2068 * take the original packet, copy it, and patch in our new ID */
2069 r
= dns_packet_dup(&p
, t
->bypass
);
2073 r
= dns_packet_new_query(
2074 &p
, t
->scope
->protocol
,
2075 /* min_alloc_dsize = */ 0,
2076 /* dnssec_cd = */ !FLAGS_SET(t
->query_flags
, SD_RESOLVED_NO_VALIDATE
) &&
2077 t
->scope
->dnssec_mode
!= DNSSEC_NO
);
2081 r
= dns_packet_append_key(p
, dns_transaction_key(t
), 0, NULL
);
2085 DNS_PACKET_HEADER(p
)->qdcount
= htobe16(1);
2088 DNS_PACKET_HEADER(p
)->id
= t
->id
;
2090 t
->sent
= TAKE_PTR(p
);
2094 int dns_transaction_go(DnsTransaction
*t
) {
2097 char key_str
[DNS_RESOURCE_KEY_STRING_MAX
];
2101 /* Returns > 0 if the transaction is now pending, returns 0 if could be processed immediately and has
2102 * finished now. In the latter case, the transaction and query candidate objects must not be accessed.
2105 assert_se(sd_event_now(t
->scope
->manager
->event
, CLOCK_BOOTTIME
, &ts
) >= 0);
2107 r
= dns_transaction_prepare(t
, ts
);
2111 log_debug("Firing %s transaction %" PRIu16
" for <%s> scope %s on %s/%s (validate=%s).",
2112 t
->bypass
? "bypass" : "regular",
2114 dns_resource_key_to_string(dns_transaction_key(t
), key_str
, sizeof key_str
),
2115 dns_protocol_to_string(t
->scope
->protocol
),
2116 t
->scope
->link
? t
->scope
->link
->ifname
: "*",
2117 af_to_name_short(t
->scope
->family
),
2118 yes_no(!FLAGS_SET(t
->query_flags
, SD_RESOLVED_NO_VALIDATE
)));
2120 if (!t
->initial_jitter_scheduled
&&
2121 IN_SET(t
->scope
->protocol
, DNS_PROTOCOL_LLMNR
, DNS_PROTOCOL_MDNS
)) {
2124 /* RFC 4795 Section 2.7 suggests all LLMNR queries should be delayed by a random time from 0 to
2126 * RFC 6762 Section 8.1 suggests initial probe queries should be delayed by a random time from
2129 t
->initial_jitter_scheduled
= true;
2132 switch (t
->scope
->protocol
) {
2134 case DNS_PROTOCOL_LLMNR
:
2135 jitter
= random_u64_range(LLMNR_JITTER_INTERVAL_USEC
);
2138 case DNS_PROTOCOL_MDNS
:
2140 jitter
= random_u64_range(MDNS_PROBING_INTERVAL_USEC
);
2145 assert_not_reached();
2148 r
= dns_transaction_setup_timeout(t
, jitter
, ts
);
2152 log_debug("Delaying %s transaction %" PRIu16
" for " USEC_FMT
"us.",
2153 dns_protocol_to_string(t
->scope
->protocol
),
2159 /* Otherwise, we need to ask the network */
2160 r
= dns_transaction_make_packet(t
);
2164 if (t
->scope
->protocol
== DNS_PROTOCOL_LLMNR
&&
2165 (dns_name_endswith(dns_resource_key_name(dns_transaction_key(t
)), "in-addr.arpa") > 0 ||
2166 dns_name_endswith(dns_resource_key_name(dns_transaction_key(t
)), "ip6.arpa") > 0)) {
2168 /* RFC 4795, Section 2.4. says reverse lookups shall
2169 * always be made via TCP on LLMNR */
2170 r
= dns_transaction_emit_tcp(t
);
2172 /* Try via UDP, and if that fails due to large size or lack of
2173 * support try via TCP */
2174 r
= dns_transaction_emit_udp(t
);
2176 log_debug("Sending query via TCP since it is too large.");
2177 else if (r
== -EAGAIN
)
2178 log_debug("Sending query via TCP since UDP isn't supported or DNS-over-TLS is selected.");
2179 else if (r
== -EPERM
)
2180 log_debug("Sending query via TCP since UDP is blocked.");
2181 if (IN_SET(r
, -EMSGSIZE
, -EAGAIN
, -EPERM
))
2182 r
= dns_transaction_emit_tcp(t
);
2185 if (t
->scope
->protocol
!= DNS_PROTOCOL_DNS
)
2188 /* One of our own stub listeners */
2189 log_debug_errno(r
, "Detected that specified DNS server is our own extra listener, switching DNS servers.");
2191 dns_scope_next_dns_server(t
->scope
, t
->server
);
2193 if (dns_scope_get_dns_server(t
->scope
) == t
->server
) {
2194 log_debug_errno(r
, "Still pointing to extra listener after switching DNS servers, refusing operation.");
2195 dns_transaction_complete(t
, DNS_TRANSACTION_STUB_LOOP
);
2199 return dns_transaction_go(t
);
2202 /* No servers to send this to? */
2203 dns_transaction_complete(t
, DNS_TRANSACTION_NO_SERVERS
);
2206 if (r
== -EOPNOTSUPP
) {
2207 /* Tried to ask for DNSSEC RRs, on a server that doesn't do DNSSEC */
2208 dns_transaction_complete(t
, DNS_TRANSACTION_RR_TYPE_UNSUPPORTED
);
2211 if (t
->scope
->protocol
== DNS_PROTOCOL_LLMNR
&& ERRNO_IS_NEG_DISCONNECT(r
)) {
2212 /* On LLMNR, if we cannot connect to a host via TCP when doing reverse lookups. This means we cannot
2213 * answer this request with this protocol. */
2214 dns_transaction_complete(t
, DNS_TRANSACTION_NOT_FOUND
);
2218 if (t
->scope
->protocol
!= DNS_PROTOCOL_DNS
)
2221 /* Couldn't send? Try immediately again, with a new server */
2222 dns_scope_next_dns_server(t
->scope
, t
->server
);
2224 return dns_transaction_go(t
);
2227 usec_t timeout
= transaction_get_resend_timeout(t
);
2228 r
= dns_transaction_setup_timeout(t
, timeout
, usec_add(ts
, timeout
));
2235 static int dns_transaction_find_cyclic(DnsTransaction
*t
, DnsTransaction
*aux
) {
2242 /* Try to find cyclic dependencies between transaction objects */
2247 SET_FOREACH(n
, aux
->dnssec_transactions
) {
2248 r
= dns_transaction_find_cyclic(t
, n
);
2256 static int dns_transaction_add_dnssec_transaction(DnsTransaction
*t
, DnsResourceKey
*key
, DnsTransaction
**ret
) {
2257 _cleanup_(dns_transaction_gcp
) DnsTransaction
*aux
= NULL
;
2264 aux
= dns_scope_find_transaction(t
->scope
, key
, t
->query_flags
);
2266 r
= dns_transaction_new(&aux
, t
->scope
, key
, NULL
, t
->query_flags
);
2270 if (set_contains(t
->dnssec_transactions
, aux
)) {
2275 r
= dns_transaction_find_cyclic(t
, aux
);
2279 char s
[DNS_RESOURCE_KEY_STRING_MAX
], saux
[DNS_RESOURCE_KEY_STRING_MAX
];
2281 return log_debug_errno(SYNTHETIC_ERRNO(ELOOP
),
2282 "Potential cyclic dependency, refusing to add transaction %" PRIu16
" (%s) as dependency for %" PRIu16
" (%s).",
2284 dns_resource_key_to_string(dns_transaction_key(t
), s
, sizeof s
),
2286 dns_resource_key_to_string(dns_transaction_key(aux
), saux
, sizeof saux
));
2290 r
= set_ensure_allocated(&aux
->notify_transactions_done
, NULL
);
2294 r
= set_ensure_put(&t
->dnssec_transactions
, NULL
, aux
);
2298 r
= set_ensure_put(&aux
->notify_transactions
, NULL
, t
);
2300 (void) set_remove(t
->dnssec_transactions
, aux
);
2304 *ret
= TAKE_PTR(aux
);
2308 static int dns_transaction_request_dnssec_rr_full(DnsTransaction
*t
, DnsResourceKey
*key
, DnsTransaction
**ret
) {
2309 _cleanup_(dns_answer_unrefp
) DnsAnswer
*a
= NULL
;
2310 DnsTransaction
*aux
;
2316 /* Try to get the data from the trust anchor */
2317 r
= dns_trust_anchor_lookup_positive(&t
->scope
->manager
->trust_anchor
, key
, &a
);
2321 r
= dns_answer_extend(&t
->validated_keys
, a
);
2330 /* This didn't work, ask for it via the network/cache then. */
2331 r
= dns_transaction_add_dnssec_transaction(t
, key
, &aux
);
2332 if (r
== -ELOOP
) { /* This would result in a cyclic dependency */
2340 if (aux
->state
== DNS_TRANSACTION_NULL
) {
2341 r
= dns_transaction_go(aux
);
2351 static int dns_transaction_request_dnssec_rr(DnsTransaction
*t
, DnsResourceKey
*key
) {
2354 return dns_transaction_request_dnssec_rr_full(t
, key
, NULL
);
2357 static int dns_transaction_negative_trust_anchor_lookup(DnsTransaction
*t
, const char *name
) {
2362 /* Check whether the specified name is in the NTA
2363 * database, either in the global one, or the link-local
2366 r
= dns_trust_anchor_lookup_negative(&t
->scope
->manager
->trust_anchor
, name
);
2370 if (!t
->scope
->link
)
2373 return link_negative_trust_anchor_lookup(t
->scope
->link
, name
);
2376 static int dns_transaction_has_negative_answer(DnsTransaction
*t
) {
2381 /* Checks whether the answer is negative, and lacks NSEC/NSEC3
2382 * RRs to prove it */
2384 r
= dns_transaction_has_positive_answer(t
, NULL
);
2390 /* Is this key explicitly listed as a negative trust anchor?
2391 * If so, it's nothing we need to care about */
2392 r
= dns_transaction_negative_trust_anchor_lookup(t
, dns_resource_key_name(dns_transaction_key(t
)));
2398 static int dns_transaction_is_primary_response(DnsTransaction
*t
, DnsResourceRecord
*rr
) {
2404 /* Check if the specified RR is the "primary" response,
2405 * i.e. either matches the question precisely or is a
2406 * CNAME/DNAME for it. */
2408 r
= dns_resource_key_match_rr(dns_transaction_key(t
), rr
, NULL
);
2412 return dns_resource_key_match_cname_or_dname(dns_transaction_key(t
), rr
->key
, NULL
);
2415 static bool dns_transaction_dnssec_supported(DnsTransaction
*t
) {
2418 /* Checks whether our transaction's DNS server is assumed to be compatible with DNSSEC. Returns false as soon
2419 * as we changed our mind about a server, and now believe it is incompatible with DNSSEC. */
2421 if (t
->scope
->protocol
!= DNS_PROTOCOL_DNS
)
2424 /* If we have picked no server, then we are working from the cache or some other source, and DNSSEC might well
2425 * be supported, hence return true. */
2429 /* Note that we do not check the feature level actually used for the transaction but instead the feature level
2430 * the server is known to support currently, as the transaction feature level might be lower than what the
2431 * server actually supports, since we might have downgraded this transaction's feature level because we got a
2432 * SERVFAIL earlier and wanted to check whether downgrading fixes it. */
2434 return dns_server_dnssec_supported(t
->server
);
2437 static bool dns_transaction_dnssec_supported_full(DnsTransaction
*t
) {
2442 /* Checks whether our transaction our any of the auxiliary transactions couldn't do DNSSEC. */
2444 if (!dns_transaction_dnssec_supported(t
))
2447 SET_FOREACH(dt
, t
->dnssec_transactions
)
2448 if (!dns_transaction_dnssec_supported(dt
))
2454 int dns_transaction_request_dnssec_keys(DnsTransaction
*t
) {
2455 DnsResourceRecord
*rr
;
2457 /* Have we already requested a record that would be sufficient to validate an insecure delegation? */
2458 bool chased_insecure
= false;
2464 * Retrieve all auxiliary RRs for the answer we got, so that
2465 * we can verify signatures or prove that RRs are rightfully
2466 * unsigned. Specifically:
2468 * - For RRSIG we get the matching DNSKEY
2469 * - For DNSKEY we get the matching DS
2470 * - For unsigned SOA/NS we get the matching DS
2471 * - For unsigned CNAME/DNAME/DS we get the parent DS RR
2472 * - For other unsigned RRs we get the matching DS RR
2473 * - For SOA/NS queries with no matching response RR, and no NSEC/NSEC3, the DS RR
2474 * - For DS queries with no matching response RRs, and no NSEC/NSEC3, the parent's DS RR
2475 * - For other queries with no matching response RRs, and no NSEC/NSEC3, the DS RR
2478 if (FLAGS_SET(t
->query_flags
, SD_RESOLVED_NO_VALIDATE
) || t
->scope
->dnssec_mode
== DNSSEC_NO
)
2480 if (t
->answer_source
!= DNS_TRANSACTION_NETWORK
)
2481 return 0; /* We only need to validate stuff from the network */
2482 if (!dns_transaction_dnssec_supported(t
))
2483 return 0; /* If we can't do DNSSEC anyway there's no point in getting the auxiliary RRs */
2485 DNS_ANSWER_FOREACH(rr
, t
->answer
) {
2487 if (dns_type_is_pseudo(rr
->key
->type
))
2490 /* If this RR is in the negative trust anchor, we don't need to validate it. */
2491 r
= dns_transaction_negative_trust_anchor_lookup(t
, dns_resource_key_name(rr
->key
));
2497 switch (rr
->key
->type
) {
2499 case DNS_TYPE_RRSIG
: {
2500 /* For each RRSIG we request the matching DNSKEY */
2501 _cleanup_(dns_resource_key_unrefp
) DnsResourceKey
*dnskey
= NULL
;
2502 DnsTransaction
*aux
;
2504 /* If this RRSIG is about a DNSKEY RR and the
2505 * signer is the same as the owner, then we
2506 * already have the DNSKEY, and we don't have
2507 * to look for more. */
2508 if (rr
->rrsig
.type_covered
== DNS_TYPE_DNSKEY
) {
2509 r
= dns_name_equal(rr
->rrsig
.signer
, dns_resource_key_name(rr
->key
));
2516 /* If the signer is not a parent of our
2517 * original query, then this is about an
2518 * auxiliary RRset, but not anything we asked
2519 * for. In this case we aren't interested,
2520 * because we don't want to request additional
2521 * RRs for stuff we didn't really ask for, and
2522 * also to avoid request loops, where
2523 * additional RRs from one transaction result
2524 * in another transaction whose additional RRs
2525 * point back to the original transaction, and
2527 r
= dns_name_endswith(dns_resource_key_name(dns_transaction_key(t
)), rr
->rrsig
.signer
);
2533 dnskey
= dns_resource_key_new(rr
->key
->class, DNS_TYPE_DNSKEY
, rr
->rrsig
.signer
);
2537 log_debug("Requesting DNSKEY to validate transaction %" PRIu16
" (%s, RRSIG with key tag: %" PRIu16
").",
2538 t
->id
, dns_resource_key_name(rr
->key
), rr
->rrsig
.key_tag
);
2539 r
= dns_transaction_request_dnssec_rr_full(t
, dnskey
, &aux
);
2543 /* If we are requesting a DNSKEY, we can anticipate that we will want the matching DS
2544 * in the near future. Let's request it in advance so we don't have to wait in the
2547 _cleanup_(dns_resource_key_unrefp
) DnsResourceKey
*ds
=
2548 dns_resource_key_new(rr
->key
->class, DNS_TYPE_DS
, dns_resource_key_name(dnskey
));
2551 r
= dns_transaction_request_dnssec_rr(t
, ds
);
2558 case DNS_TYPE_DNSKEY
: {
2559 /* For each DNSKEY we request the matching DS */
2560 _cleanup_(dns_resource_key_unrefp
) DnsResourceKey
*ds
= NULL
;
2562 /* If the DNSKEY we are looking at is not for
2563 * zone we are interested in, nor any of its
2564 * parents, we aren't interested, and don't
2565 * request it. After all, we don't want to end
2566 * up in request loops, and want to keep
2567 * additional traffic down. */
2569 r
= dns_name_endswith(dns_resource_key_name(dns_transaction_key(t
)), dns_resource_key_name(rr
->key
));
2575 ds
= dns_resource_key_new(rr
->key
->class, DNS_TYPE_DS
, dns_resource_key_name(rr
->key
));
2579 log_debug("Requesting DS to validate transaction %" PRIu16
" (%s, DNSKEY with key tag: %" PRIu16
").",
2580 t
->id
, dns_resource_key_name(rr
->key
), dnssec_keytag(rr
, false));
2581 r
= dns_transaction_request_dnssec_rr(t
, ds
);
2590 _cleanup_(dns_resource_key_unrefp
) DnsResourceKey
*ds
= NULL
;
2592 /* For an unsigned SOA or NS, try to acquire
2593 * the matching DS RR, as we are at a zone cut
2594 * then, and whether a DS exists tells us
2595 * whether the zone is signed. Do so only if
2596 * this RR matches our original question,
2599 r
= dns_resource_key_match_rr(dns_transaction_key(t
), rr
, NULL
);
2603 /* Hmm, so this SOA RR doesn't match our original question. In this case, maybe this is
2604 * a negative reply, and we need the SOA RR's TTL in order to cache a negative entry?
2605 * If so, we need to validate it, too. */
2607 r
= dns_answer_match_key(t
->answer
, dns_transaction_key(t
), NULL
);
2610 if (r
> 0) /* positive reply, we won't need the SOA and hence don't need to validate
2614 /* Only bother with this if the SOA/NS RR we are looking at is actually a parent of
2615 * what we are looking for, otherwise there's no value in it for us. */
2616 r
= dns_name_endswith(dns_resource_key_name(dns_transaction_key(t
)), dns_resource_key_name(rr
->key
));
2622 /* If we were looking for the DS RR, don't request it again. */
2623 if (dns_transaction_key(t
)->type
== DNS_TYPE_DS
)
2627 r
= dnssec_has_rrsig(t
->answer
, rr
->key
);
2633 chased_insecure
= true;
2634 ds
= dns_resource_key_new(rr
->key
->class, DNS_TYPE_DS
, dns_resource_key_name(rr
->key
));
2638 log_debug("Requesting DS to validate transaction %" PRIu16
" (%s, unsigned SOA/NS RRset).",
2639 t
->id
, dns_resource_key_name(rr
->key
));
2640 r
= dns_transaction_request_dnssec_rr(t
, ds
);
2648 case DNS_TYPE_CNAME
:
2649 case DNS_TYPE_DNAME
: {
2650 _cleanup_(dns_resource_key_unrefp
) DnsResourceKey
*ds
= NULL
;
2653 /* CNAMEs and DNAMEs cannot be located at a
2654 * zone apex, hence ask for the parent DS for
2655 * unsigned CNAME/DNAME RRs, maybe that's the
2656 * apex. But do all that only if this is
2657 * actually a response to our original
2660 * Similar for DS RRs, which are signed when
2661 * the parent SOA is signed. */
2663 r
= dns_transaction_is_primary_response(t
, rr
);
2669 r
= dnssec_has_rrsig(t
->answer
, rr
->key
);
2675 r
= dns_answer_has_dname_for_cname(t
->answer
, rr
);
2681 name
= dns_resource_key_name(rr
->key
);
2682 r
= dns_name_parent(&name
);
2688 ds
= dns_resource_key_new(rr
->key
->class, DNS_TYPE_DS
, name
);
2692 log_debug("Requesting parent DS to validate transaction %" PRIu16
" (%s, unsigned CNAME/DNAME/DS RRset).",
2693 t
->id
, dns_resource_key_name(rr
->key
));
2694 r
= dns_transaction_request_dnssec_rr(t
, ds
);
2698 if (t
->scope
->dnssec_mode
== DNSSEC_ALLOW_DOWNGRADE
&& dns_name_is_root(name
)) {
2699 _cleanup_(dns_resource_key_unrefp
) DnsResourceKey
*soa
= NULL
;
2700 /* We made it all the way to the root zone. If we are in allow-downgrade
2701 * mode, we need to make at least one request that we can be certain should
2702 * have been signed, to test for servers that are not dnssec aware. */
2703 soa
= dns_resource_key_new(rr
->key
->class, DNS_TYPE_SOA
, name
);
2707 log_debug("Requesting root zone SOA to probe dnssec support.");
2708 r
= dns_transaction_request_dnssec_rr(t
, soa
);
2717 _cleanup_(dns_resource_key_unrefp
) DnsResourceKey
*ds
= NULL
;
2719 /* For other unsigned RRsets (including
2720 * NSEC/NSEC3!), look for proof the zone is
2721 * unsigned, by requesting the DS RR of the
2722 * zone. However, do so only if they are
2723 * directly relevant to our original
2726 r
= dns_transaction_is_primary_response(t
, rr
);
2732 r
= dnssec_has_rrsig(t
->answer
, rr
->key
);
2738 ds
= dns_resource_key_new(rr
->key
->class, DNS_TYPE_DS
, dns_resource_key_name(rr
->key
));
2742 log_debug("Requesting DS to validate transaction %" PRIu16
" (%s, unsigned non-SOA/NS RRset <%s>).",
2743 t
->id
, dns_resource_key_name(rr
->key
), dns_resource_record_to_string(rr
));
2744 r
= dns_transaction_request_dnssec_rr(t
, ds
);
2751 /* Above, we requested everything necessary to validate what
2752 * we got. Now, let's request what we need to validate what we
2755 r
= dns_transaction_has_negative_answer(t
);
2759 const char *name
= dns_resource_key_name(dns_transaction_key(t
));
2760 bool was_signed
= dns_answer_contains_nsec_or_nsec3(t
->answer
);
2762 /* If the response is empty, seek the DS for this name, just in case we're at a zone cut
2763 * already, unless we just requested the DS, in which case we have to ask the parent to make
2766 * If this was an SOA or NS request, we could also skip to the parent, but in real world
2767 * setups there are too many broken DNS servers (Hello, incapdns.net!) where non-terminal
2768 * zones return NXDOMAIN even though they have further children. */
2770 if (chased_insecure
|| was_signed
)
2771 /* In this case we already requested what we need above. */
2773 else if (dns_transaction_key(t
)->type
== DNS_TYPE_DS
)
2774 /* If the DS response is empty, we'll walk up the dns labels requesting DS until we
2775 * find a referral to the SOA or hit it anyway and get a positive DS response. */
2776 if (dns_name_parent(&name
) <= 0)
2780 _cleanup_(dns_resource_key_unrefp
) DnsResourceKey
*ds
= NULL
;
2782 log_debug("Requesting DS (%s %s) to validate transaction %" PRIu16
" (%s empty response).",
2783 special_glyph(SPECIAL_GLYPH_ARROW_RIGHT
), name
, t
->id
,
2784 dns_resource_key_name(dns_transaction_key(t
)));
2786 ds
= dns_resource_key_new(dns_transaction_key(t
)->class, DNS_TYPE_DS
, name
);
2790 r
= dns_transaction_request_dnssec_rr(t
, ds
);
2796 return dns_transaction_dnssec_is_live(t
);
2799 void dns_transaction_notify(DnsTransaction
*t
, DnsTransaction
*source
) {
2803 /* Invoked whenever any of our auxiliary DNSSEC transactions completed its work. If the state is still PENDING,
2804 we are still in the loop that adds further DNSSEC transactions, hence don't check if we are ready yet. If
2805 the state is VALIDATING however, we should check if we are complete now. */
2807 if (t
->state
== DNS_TRANSACTION_VALIDATING
)
2808 dns_transaction_process_dnssec(t
);
2811 static int dns_transaction_validate_dnskey_by_ds(DnsTransaction
*t
) {
2812 DnsAnswerItem
*item
;
2817 /* Add all DNSKEY RRs from the answer that are validated by DS
2818 * RRs from the list of validated keys to the list of
2819 * validated keys. */
2821 DNS_ANSWER_FOREACH_ITEM(item
, t
->answer
) {
2823 r
= dnssec_verify_dnskey_by_ds_search(item
->rr
, t
->validated_keys
);
2829 /* If so, the DNSKEY is validated too. */
2830 r
= dns_answer_add_extend(&t
->validated_keys
, item
->rr
, item
->ifindex
, item
->flags
|DNS_ANSWER_AUTHENTICATED
, item
->rrsig
);
2838 static int dns_transaction_requires_rrsig(DnsTransaction
*t
, DnsResourceRecord
*rr
) {
2844 /* Checks if the RR we are looking for must be signed with an
2845 * RRSIG. This is used for positive responses. */
2847 if (t
->scope
->dnssec_mode
== DNSSEC_NO
)
2850 if (dns_type_is_pseudo(rr
->key
->type
))
2853 r
= dns_transaction_negative_trust_anchor_lookup(t
, dns_resource_key_name(rr
->key
));
2859 switch (rr
->key
->type
) {
2861 case DNS_TYPE_RRSIG
:
2862 /* RRSIGs are the signatures themselves, they need no signing. */
2869 /* For SOA or NS RRs we look for a matching DS transaction */
2870 SET_FOREACH(dt
, t
->dnssec_transactions
) {
2872 if (dns_transaction_key(dt
)->class != rr
->key
->class)
2874 if (dns_transaction_key(dt
)->type
!= DNS_TYPE_DS
)
2877 r
= dns_name_endswith(dns_resource_key_name(rr
->key
), dns_resource_key_name(dns_transaction_key(dt
)));
2883 /* We found a DS transactions for the SOA/NS
2884 * RRs we are looking at. If it discovered signed DS
2885 * RRs, then we need to be signed, too. */
2887 if (!FLAGS_SET(dt
->answer_query_flags
, SD_RESOLVED_AUTHENTICATED
))
2890 return dns_answer_match_key(dt
->answer
, dns_transaction_key(dt
), NULL
);
2893 /* We found nothing that proves this is safe to leave
2894 * this unauthenticated, hence ask inist on
2895 * authentication. */
2900 case DNS_TYPE_CNAME
:
2901 case DNS_TYPE_DNAME
: {
2902 const char *parent
= NULL
;
2906 * CNAME/DNAME RRs cannot be located at a zone apex, hence look directly for the parent DS.
2908 * DS RRs are signed if the parent is signed, hence also look at the parent DS
2911 SET_FOREACH(dt
, t
->dnssec_transactions
) {
2913 if (dns_transaction_key(dt
)->class != rr
->key
->class)
2915 if (dns_transaction_key(dt
)->type
!= DNS_TYPE_DS
)
2919 parent
= dns_resource_key_name(rr
->key
);
2920 r
= dns_name_parent(&parent
);
2924 if (rr
->key
->type
== DNS_TYPE_DS
)
2927 /* A CNAME/DNAME without a parent? That's sooo weird. */
2928 return log_debug_errno(SYNTHETIC_ERRNO(EBADMSG
),
2929 "Transaction %" PRIu16
" claims CNAME/DNAME at root. Refusing.", t
->id
);
2933 r
= dns_name_endswith(parent
, dns_resource_key_name(dns_transaction_key(dt
)));
2939 if (!FLAGS_SET(dt
->answer_query_flags
, SD_RESOLVED_AUTHENTICATED
))
2942 /* We expect this to be signed when the DS record exists, and don't expect it to be
2943 * signed when the DS record is proven not to exist. */
2944 return dns_answer_match_key(dt
->answer
, dns_transaction_key(dt
), NULL
);
2953 /* Any other kind of RR (including DNSKEY/NSEC/NSEC3). Let's see if our DS lookup was authenticated */
2955 SET_FOREACH(dt
, t
->dnssec_transactions
) {
2956 if (dns_transaction_key(dt
)->class != rr
->key
->class)
2958 if (dns_transaction_key(dt
)->type
!= DNS_TYPE_DS
)
2961 r
= dns_name_endswith(dns_resource_key_name(rr
->key
), dns_resource_key_name(dns_transaction_key(dt
)));
2967 if (!FLAGS_SET(dt
->answer_query_flags
, SD_RESOLVED_AUTHENTICATED
))
2970 /* We expect this to be signed when the DS record exists, and don't expect it to be
2971 * signed when the DS record is proven not to exist. */
2972 return dns_answer_match_key(dt
->answer
, dns_transaction_key(dt
), NULL
);
2979 static int dns_transaction_in_private_tld(DnsTransaction
*t
, const DnsResourceKey
*key
) {
2984 /* If DNSSEC downgrade mode is on, checks whether the
2985 * specified RR is one level below a TLD we have proven not to
2986 * exist. In such a case we assume that this is a private
2987 * domain, and permit it.
2989 * This detects cases like the Fritz!Box router networks. Each
2990 * Fritz!Box router serves a private "fritz.box" zone, in the
2991 * non-existing TLD "box". Requests for the "fritz.box" domain
2992 * are served by the router itself, while requests for the
2993 * "box" domain will result in NXDOMAIN.
2995 * Note that this logic is unable to detect cases where a
2996 * router serves a private DNS zone directly under
2997 * non-existing TLD. In such a case we cannot detect whether
2998 * the TLD is supposed to exist or not, as all requests we
2999 * make for it will be answered by the router's zone, and not
3000 * by the root zone. */
3004 if (t
->scope
->dnssec_mode
!= DNSSEC_ALLOW_DOWNGRADE
)
3005 return false; /* In strict DNSSEC mode what doesn't exist, doesn't exist */
3007 tld
= dns_resource_key_name(key
);
3008 r
= dns_name_parent(&tld
);
3012 return false; /* Already the root domain */
3014 if (!dns_name_is_single_label(tld
))
3017 SET_FOREACH(dt
, t
->dnssec_transactions
) {
3019 if (dns_transaction_key(dt
)->class != key
->class)
3022 r
= dns_name_equal(dns_resource_key_name(dns_transaction_key(dt
)), tld
);
3028 /* We found an auxiliary lookup we did for the TLD. If
3029 * that returned with NXDOMAIN, we know the TLD didn't
3030 * exist, and hence this might be a private zone. */
3032 return dt
->answer_rcode
== DNS_RCODE_NXDOMAIN
;
3038 static int dns_transaction_requires_nsec(DnsTransaction
*t
) {
3039 char key_str
[DNS_RESOURCE_KEY_STRING_MAX
];
3046 /* Checks if we need to insist on NSEC/NSEC3 RRs for proving
3047 * this negative reply */
3049 if (t
->scope
->dnssec_mode
== DNSSEC_NO
)
3052 if (dns_type_is_pseudo(dns_transaction_key(t
)->type
))
3055 r
= dns_transaction_negative_trust_anchor_lookup(t
, dns_resource_key_name(dns_transaction_key(t
)));
3061 r
= dns_transaction_in_private_tld(t
, dns_transaction_key(t
));
3065 /* The lookup is from a TLD that is proven not to
3066 * exist, and we are in downgrade mode, hence ignore
3067 * that fact that we didn't get any NSEC RRs. */
3069 log_info("Detected a negative query %s in a private DNS zone, permitting unsigned response.",
3070 dns_resource_key_to_string(dns_transaction_key(t
), key_str
, sizeof key_str
));
3074 name
= dns_resource_key_name(dns_transaction_key(t
));
3076 if (IN_SET(dns_transaction_key(t
)->type
, DNS_TYPE_DS
, DNS_TYPE_CNAME
, DNS_TYPE_DNAME
)) {
3077 /* We got a negative reply for this DS/CNAME/DNAME lookup? Check the parent in this case to
3078 * see if this answer should have been signed. */
3079 r
= dns_name_parent(&name
);
3086 /* For all other RRs we check the DS on the same level to see
3087 * if it's signed. */
3089 SET_FOREACH(dt
, t
->dnssec_transactions
) {
3090 if (dns_transaction_key(dt
)->class != dns_transaction_key(t
)->class)
3092 if (dns_transaction_key(dt
)->type
!= DNS_TYPE_DS
)
3095 r
= dns_name_endswith(name
, dns_resource_key_name(dns_transaction_key(dt
)));
3101 if (!FLAGS_SET(dt
->answer_query_flags
, SD_RESOLVED_AUTHENTICATED
))
3104 /* We expect this to be signed when the DS record exists, and don't expect it to be signed
3105 * when the DS record is proven not to exist. */
3106 return dns_answer_match_key(dt
->answer
, dns_transaction_key(dt
), NULL
);
3109 /* If in doubt, require NSEC/NSEC3 */
3113 static int dns_transaction_dnskey_authenticated(DnsTransaction
*t
, DnsResourceRecord
*rr
) {
3114 DnsResourceRecord
*rrsig
;
3118 /* Checks whether any of the DNSKEYs used for the RRSIGs for
3119 * the specified RRset is authenticated (i.e. has a matching
3122 r
= dns_transaction_negative_trust_anchor_lookup(t
, dns_resource_key_name(rr
->key
));
3128 DNS_ANSWER_FOREACH(rrsig
, t
->answer
) {
3131 r
= dnssec_key_match_rrsig(rr
->key
, rrsig
);
3137 SET_FOREACH(dt
, t
->dnssec_transactions
) {
3139 if (dns_transaction_key(dt
)->class != rr
->key
->class)
3142 if (dns_transaction_key(dt
)->type
== DNS_TYPE_DNSKEY
) {
3144 r
= dns_name_equal(dns_resource_key_name(dns_transaction_key(dt
)), rrsig
->rrsig
.signer
);
3150 /* OK, we found an auxiliary DNSKEY lookup. If that lookup is authenticated,
3153 if (FLAGS_SET(dt
->answer_query_flags
, SD_RESOLVED_AUTHENTICATED
))
3158 } else if (dns_transaction_key(dt
)->type
== DNS_TYPE_DS
) {
3160 r
= dns_name_equal(dns_resource_key_name(dns_transaction_key(dt
)), rrsig
->rrsig
.signer
);
3166 /* OK, we found an auxiliary DS lookup. If that lookup is authenticated and
3167 * non-zero, we won! */
3169 if (!FLAGS_SET(dt
->answer_query_flags
, SD_RESOLVED_AUTHENTICATED
))
3172 return dns_answer_match_key(dt
->answer
, dns_transaction_key(dt
), NULL
);
3177 return found
? false : -ENXIO
;
3180 static int dns_transaction_known_signed(DnsTransaction
*t
, DnsResourceRecord
*rr
) {
3184 /* We know that the root domain is signed, hence if it appears
3185 * not to be signed, there's a problem with the DNS server */
3187 return rr
->key
->class == DNS_CLASS_IN
&&
3188 dns_name_is_root(dns_resource_key_name(rr
->key
));
3191 static int dns_transaction_check_revoked_trust_anchors(DnsTransaction
*t
) {
3192 DnsResourceRecord
*rr
;
3197 /* Maybe warn the user that we encountered a revoked DNSKEY
3198 * for a key from our trust anchor. Note that we don't care
3199 * whether the DNSKEY can be authenticated or not. It's
3200 * sufficient if it is self-signed. */
3202 DNS_ANSWER_FOREACH(rr
, t
->answer
) {
3203 r
= dns_trust_anchor_check_revoked(&t
->scope
->manager
->trust_anchor
, rr
, t
->answer
);
3211 static int dns_transaction_invalidate_revoked_keys(DnsTransaction
*t
) {
3217 /* Removes all DNSKEY/DS objects from t->validated_keys that
3218 * our trust anchors database considers revoked. */
3221 DnsResourceRecord
*rr
;
3225 DNS_ANSWER_FOREACH(rr
, t
->validated_keys
) {
3226 r
= dns_trust_anchor_is_revoked(&t
->scope
->manager
->trust_anchor
, rr
);
3230 r
= dns_answer_remove_by_rr(&t
->validated_keys
, rr
);
3244 static int dns_transaction_copy_validated(DnsTransaction
*t
) {
3250 /* Copy all validated RRs from the auxiliary DNSSEC transactions into our set of validated RRs */
3252 SET_FOREACH(dt
, t
->dnssec_transactions
) {
3254 if (DNS_TRANSACTION_IS_LIVE(dt
->state
))
3257 if (!FLAGS_SET(dt
->answer_query_flags
, SD_RESOLVED_AUTHENTICATED
))
3260 r
= dns_answer_extend(&t
->validated_keys
, dt
->answer
);
3269 DNSSEC_PHASE_DNSKEY
, /* Phase #1, only validate DNSKEYs */
3270 DNSSEC_PHASE_NSEC
, /* Phase #2, only validate NSEC+NSEC3 */
3271 DNSSEC_PHASE_ALL
, /* Phase #3, validate everything else */
3274 static int dnssec_validate_records(
3278 unsigned *nvalidations
,
3279 DnsAnswer
**validated
) {
3281 DnsResourceRecord
*rr
;
3284 assert(nvalidations
);
3286 /* Returns negative on error, 0 if validation failed, 1 to restart validation, 2 when finished. */
3288 DNS_ANSWER_FOREACH(rr
, t
->answer
) {
3289 _unused_
_cleanup_(dns_resource_record_unrefp
) DnsResourceRecord
*rr_ref
= dns_resource_record_ref(rr
);
3290 DnsResourceRecord
*rrsig
= NULL
;
3291 DnssecResult result
;
3293 switch (rr
->key
->type
) {
3294 case DNS_TYPE_RRSIG
:
3297 case DNS_TYPE_DNSKEY
:
3298 /* We validate DNSKEYs only in the DNSKEY and ALL phases */
3299 if (phase
== DNSSEC_PHASE_NSEC
)
3304 case DNS_TYPE_NSEC3
:
3307 /* We validate NSEC/NSEC3 only in the NSEC and ALL phases */
3308 if (phase
== DNSSEC_PHASE_DNSKEY
)
3313 /* We validate all other RRs only in the ALL phases */
3314 if (phase
!= DNSSEC_PHASE_ALL
)
3318 r
= dnssec_verify_rrset_search(
3329 log_debug("Looking at %s: %s", strna(dns_resource_record_to_string(rr
)), dnssec_result_to_string(result
));
3331 if (result
== DNSSEC_VALIDATED
) {
3334 if (rr
->key
->type
== DNS_TYPE_DNSKEY
) {
3335 /* If we just validated a DNSKEY RRset, then let's add these keys to
3336 * the set of validated keys for this transaction. */
3338 r
= dns_answer_copy_by_key(&t
->validated_keys
, t
->answer
, rr
->key
, DNS_ANSWER_AUTHENTICATED
, rrsig
);
3342 /* Some of the DNSKEYs we just added might already have been revoked,
3343 * remove them again in that case. */
3344 r
= dns_transaction_invalidate_revoked_keys(t
);
3349 /* Add the validated RRset to the new list of validated RRsets, and remove it from
3350 * the unvalidated RRsets. We mark the RRset as authenticated and cacheable. */
3351 r
= dns_answer_move_by_key(validated
, &t
->answer
, rr
->key
, DNS_ANSWER_AUTHENTICATED
|DNS_ANSWER_CACHEABLE
, rrsig
);
3355 manager_dnssec_verdict(t
->scope
->manager
, DNSSEC_SECURE
, rr
->key
);
3357 /* Exit the loop, we dropped something from the answer, start from the beginning */
3361 /* If we haven't read all DNSKEYs yet a negative result of the validation is irrelevant, as
3362 * there might be more DNSKEYs coming. Similar, if we haven't read all NSEC/NSEC3 RRs yet,
3363 * we cannot do positive wildcard proofs yet, as those require the NSEC/NSEC3 RRs. */
3364 if (phase
!= DNSSEC_PHASE_ALL
)
3367 if (result
== DNSSEC_VALIDATED_WILDCARD
) {
3368 bool authenticated
= false;
3373 /* This RRset validated, but as a wildcard. This means we need
3374 * to prove via NSEC/NSEC3 that no matching non-wildcard RR exists. */
3376 /* First step, determine the source of synthesis */
3377 r
= dns_resource_record_source(rrsig
, &source
);
3381 r
= dnssec_test_positive_wildcard(*validated
,
3382 dns_resource_key_name(rr
->key
),
3384 rrsig
->rrsig
.signer
,
3387 /* Unless the NSEC proof showed that the key really doesn't exist something is off. */
3389 result
= DNSSEC_INVALID
;
3391 r
= dns_answer_move_by_key(
3395 authenticated
? (DNS_ANSWER_AUTHENTICATED
|DNS_ANSWER_CACHEABLE
) : 0,
3400 manager_dnssec_verdict(t
->scope
->manager
, authenticated
? DNSSEC_SECURE
: DNSSEC_INSECURE
, rr
->key
);
3402 /* Exit the loop, we dropped something from the answer, start from the beginning */
3407 if (result
== DNSSEC_NO_SIGNATURE
) {
3408 r
= dns_transaction_requires_rrsig(t
, rr
);
3412 /* Data does not require signing. In that case, just copy it over,
3413 * but remember that this is by no means authenticated. */
3414 r
= dns_answer_move_by_key(
3423 manager_dnssec_verdict(t
->scope
->manager
, DNSSEC_INSECURE
, rr
->key
);
3427 r
= dns_transaction_known_signed(t
, rr
);
3431 /* This is an RR we know has to be signed. If it isn't this means
3432 * the server is not attaching RRSIGs, hence complain. */
3434 dns_server_packet_rrsig_missing(t
->server
, t
->current_feature_level
);
3436 if (t
->scope
->dnssec_mode
== DNSSEC_ALLOW_DOWNGRADE
) {
3438 /* Downgrading is OK? If so, just consider the information unsigned */
3440 r
= dns_answer_move_by_key(validated
, &t
->answer
, rr
->key
, 0, NULL
);
3444 manager_dnssec_verdict(t
->scope
->manager
, DNSSEC_INSECURE
, rr
->key
);
3448 /* Otherwise, fail */
3449 t
->answer_dnssec_result
= DNSSEC_INCOMPATIBLE_SERVER
;
3453 r
= dns_transaction_in_private_tld(t
, rr
->key
);
3457 char s
[DNS_RESOURCE_KEY_STRING_MAX
];
3459 /* The data is from a TLD that is proven not to exist, and we are in downgrade
3460 * mode, hence ignore the fact that this was not signed. */
3462 log_info("Detected RRset %s is in a private DNS zone, permitting unsigned RRs.",
3463 dns_resource_key_to_string(rr
->key
, s
, sizeof s
));
3465 r
= dns_answer_move_by_key(validated
, &t
->answer
, rr
->key
, 0, NULL
);
3469 manager_dnssec_verdict(t
->scope
->manager
, DNSSEC_INSECURE
, rr
->key
);
3474 /* https://datatracker.ietf.org/doc/html/rfc6840#section-5.2 */
3475 if (result
== DNSSEC_UNSUPPORTED_ALGORITHM
) {
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
);
3486 DNSSEC_SIGNATURE_EXPIRED
)) {
3488 r
= dns_transaction_dnskey_authenticated(t
, rr
);
3489 if (r
< 0 && r
!= -ENXIO
)
3492 /* The DNSKEY transaction was not authenticated, this means there's
3493 * no DS for this, which means it's OK if no keys are found for this signature. */
3495 r
= dns_answer_move_by_key(validated
, &t
->answer
, rr
->key
, 0, NULL
);
3499 manager_dnssec_verdict(t
->scope
->manager
, DNSSEC_INSECURE
, rr
->key
);
3504 r
= dns_transaction_is_primary_response(t
, rr
);
3508 /* Look for a matching DNAME for this CNAME */
3509 r
= dns_answer_has_dname_for_cname(t
->answer
, rr
);
3513 /* Also look among the stuff we already validated */
3514 r
= dns_answer_has_dname_for_cname(*validated
, rr
);
3522 DNSSEC_SIGNATURE_EXPIRED
,
3523 DNSSEC_NO_SIGNATURE
))
3524 manager_dnssec_verdict(t
->scope
->manager
, DNSSEC_BOGUS
, rr
->key
);
3525 else /* DNSSEC_MISSING_KEY, DNSSEC_UNSUPPORTED_ALGORITHM,
3526 or DNSSEC_TOO_MANY_VALIDATIONS */
3527 manager_dnssec_verdict(t
->scope
->manager
, DNSSEC_INDETERMINATE
, rr
->key
);
3529 /* This is a primary response to our question, and it failed validation.
3531 t
->answer_dnssec_result
= result
;
3535 /* This is a primary response, but we do have a DNAME RR
3536 * in the RR that can replay this CNAME, hence rely on
3537 * that, and we can remove the CNAME in favour of it. */
3540 /* This is just some auxiliary data. Just remove the RRset and continue. */
3541 r
= dns_answer_remove_by_key(&t
->answer
, rr
->key
);
3545 /* We dropped something from the answer, start from the beginning. */
3549 return 2; /* Finito. */
3552 int dns_transaction_validate_dnssec(DnsTransaction
*t
) {
3553 _cleanup_(dns_answer_unrefp
) DnsAnswer
*validated
= NULL
;
3555 DnsAnswerFlags flags
;
3557 char key_str
[DNS_RESOURCE_KEY_STRING_MAX
];
3561 /* We have now collected all DS and DNSKEY RRs in t->validated_keys, let's see which RRs we can now
3562 * authenticate with that. */
3564 if (FLAGS_SET(t
->query_flags
, SD_RESOLVED_NO_VALIDATE
) || t
->scope
->dnssec_mode
== DNSSEC_NO
)
3567 /* Already validated */
3568 if (t
->answer_dnssec_result
!= _DNSSEC_RESULT_INVALID
)
3571 /* Our own stuff needs no validation */
3572 if (IN_SET(t
->answer_source
, DNS_TRANSACTION_ZONE
, DNS_TRANSACTION_TRUST_ANCHOR
)) {
3573 t
->answer_dnssec_result
= DNSSEC_VALIDATED
;
3574 SET_FLAG(t
->answer_query_flags
, SD_RESOLVED_AUTHENTICATED
, true);
3578 /* Cached stuff is not affected by validation. */
3579 if (t
->answer_source
!= DNS_TRANSACTION_NETWORK
)
3582 if (!dns_transaction_dnssec_supported_full(t
)) {
3583 /* The server does not support DNSSEC, or doesn't augment responses with RRSIGs. */
3584 t
->answer_dnssec_result
= DNSSEC_INCOMPATIBLE_SERVER
;
3585 log_debug("Not validating response for %" PRIu16
", used server feature level does not support DNSSEC.", t
->id
);
3589 log_debug("Validating response from transaction %" PRIu16
" (%s).",
3591 dns_resource_key_to_string(dns_transaction_key(t
), key_str
, sizeof key_str
));
3593 /* First, see if this response contains any revoked trust
3594 * anchors we care about */
3595 r
= dns_transaction_check_revoked_trust_anchors(t
);
3599 /* Third, copy all RRs we acquired successfully from auxiliary RRs over. */
3600 r
= dns_transaction_copy_validated(t
);
3604 /* Second, see if there are DNSKEYs we already know a
3605 * validated DS for. */
3606 r
= dns_transaction_validate_dnskey_by_ds(t
);
3610 /* Fourth, remove all DNSKEY and DS RRs again that our trust
3611 * anchor says are revoked. After all we might have marked
3612 * some keys revoked above, but they might still be lingering
3613 * in our validated_keys list. */
3614 r
= dns_transaction_invalidate_revoked_keys(t
);
3618 phase
= DNSSEC_PHASE_DNSKEY
;
3619 for (unsigned nvalidations
= 0;;) {
3620 bool have_nsec
= false;
3622 r
= dnssec_validate_records(t
, phase
, &have_nsec
, &nvalidations
, &validated
);
3624 DNS_ANSWER_REPLACE(t
->answer
, TAKE_PTR(validated
));
3628 if (nvalidations
> DNSSEC_VALIDATION_MAX
) {
3629 /* This reply requires an onerous number of signature validations to verify. Let's
3630 * not waste our time trying, as this shouldn't happen for well-behaved domains
3632 t
->answer_dnssec_result
= DNSSEC_TOO_MANY_VALIDATIONS
;
3633 DNS_ANSWER_REPLACE(t
->answer
, TAKE_PTR(validated
));
3637 /* Try again as long as we managed to achieve something */
3641 if (phase
== DNSSEC_PHASE_DNSKEY
&& have_nsec
) {
3642 /* OK, we processed all DNSKEYs, and there are NSEC/NSEC3 RRs, look at those now. */
3643 phase
= DNSSEC_PHASE_NSEC
;
3647 if (phase
!= DNSSEC_PHASE_ALL
) {
3648 /* OK, we processed all DNSKEYs and NSEC/NSEC3 RRs, look at all the rest now.
3649 * Note that in this third phase we start to remove RRs we couldn't validate. */
3650 phase
= DNSSEC_PHASE_ALL
;
3658 DNS_ANSWER_REPLACE(t
->answer
, TAKE_PTR(validated
));
3660 /* At this point the answer only contains validated
3661 * RRsets. Now, let's see if it actually answers the question
3662 * we asked. If so, great! If it doesn't, then see if
3663 * NSEC/NSEC3 can prove this. */
3664 r
= dns_transaction_has_positive_answer(t
, &flags
);
3666 /* Yes, it answers the question! */
3668 if (flags
& DNS_ANSWER_AUTHENTICATED
) {
3669 /* The answer is fully authenticated, yay. */
3670 t
->answer_dnssec_result
= DNSSEC_VALIDATED
;
3671 t
->answer_rcode
= DNS_RCODE_SUCCESS
;
3672 SET_FLAG(t
->answer_query_flags
, SD_RESOLVED_AUTHENTICATED
, true);
3674 /* The answer is not fully authenticated. */
3675 t
->answer_dnssec_result
= DNSSEC_UNSIGNED
;
3676 SET_FLAG(t
->answer_query_flags
, SD_RESOLVED_AUTHENTICATED
, false);
3679 } else if (r
== 0) {
3680 DnssecNsecResult nr
;
3681 bool authenticated
= false;
3683 /* Bummer! Let's check NSEC/NSEC3 */
3684 r
= dnssec_nsec_test(t
->answer
, dns_transaction_key(t
), &nr
, &authenticated
, &t
->answer_nsec_ttl
);
3690 case DNSSEC_NSEC_NXDOMAIN
:
3691 /* NSEC proves the domain doesn't exist. Very good. */
3692 log_debug("Proved NXDOMAIN via NSEC/NSEC3 for transaction %u (%s)", t
->id
, key_str
);
3693 t
->answer_dnssec_result
= DNSSEC_VALIDATED
;
3694 t
->answer_rcode
= DNS_RCODE_NXDOMAIN
;
3695 SET_FLAG(t
->answer_query_flags
, SD_RESOLVED_AUTHENTICATED
, authenticated
);
3697 manager_dnssec_verdict(t
->scope
->manager
, authenticated
? DNSSEC_SECURE
: DNSSEC_INSECURE
, dns_transaction_key(t
));
3700 case DNSSEC_NSEC_NODATA
:
3701 /* NSEC proves that there's no data here, very good. */
3702 log_debug("Proved NODATA via NSEC/NSEC3 for transaction %u (%s)", t
->id
, key_str
);
3703 t
->answer_dnssec_result
= DNSSEC_VALIDATED
;
3704 t
->answer_rcode
= DNS_RCODE_SUCCESS
;
3705 SET_FLAG(t
->answer_query_flags
, SD_RESOLVED_AUTHENTICATED
, authenticated
);
3707 manager_dnssec_verdict(t
->scope
->manager
, authenticated
? DNSSEC_SECURE
: DNSSEC_INSECURE
, dns_transaction_key(t
));
3710 case DNSSEC_NSEC_OPTOUT
:
3711 /* NSEC3 says the data might not be signed */
3712 log_debug("Data is NSEC3 opt-out via NSEC/NSEC3 for transaction %u (%s)", t
->id
, key_str
);
3713 t
->answer_dnssec_result
= DNSSEC_UNSIGNED
;
3714 SET_FLAG(t
->answer_query_flags
, SD_RESOLVED_AUTHENTICATED
, false);
3716 manager_dnssec_verdict(t
->scope
->manager
, DNSSEC_INSECURE
, dns_transaction_key(t
));
3719 case DNSSEC_NSEC_NO_RR
:
3720 /* No NSEC data? Bummer! */
3722 r
= dns_transaction_requires_nsec(t
);
3726 t
->answer_dnssec_result
= DNSSEC_NO_SIGNATURE
;
3727 manager_dnssec_verdict(t
->scope
->manager
, DNSSEC_BOGUS
, dns_transaction_key(t
));
3729 t
->answer_dnssec_result
= DNSSEC_UNSIGNED
;
3730 SET_FLAG(t
->answer_query_flags
, SD_RESOLVED_AUTHENTICATED
, false);
3731 manager_dnssec_verdict(t
->scope
->manager
, DNSSEC_INSECURE
, dns_transaction_key(t
));
3736 case DNSSEC_NSEC_UNSUPPORTED_ALGORITHM
:
3737 /* We don't know the NSEC3 algorithm used? */
3738 t
->answer_dnssec_result
= DNSSEC_UNSUPPORTED_ALGORITHM
;
3739 manager_dnssec_verdict(t
->scope
->manager
, DNSSEC_INDETERMINATE
, dns_transaction_key(t
));
3742 case DNSSEC_NSEC_FOUND
:
3743 case DNSSEC_NSEC_CNAME
:
3744 /* NSEC says it needs to be there, but we couldn't find it? Bummer! */
3745 t
->answer_dnssec_result
= DNSSEC_NSEC_MISMATCH
;
3746 manager_dnssec_verdict(t
->scope
->manager
, DNSSEC_BOGUS
, dns_transaction_key(t
));
3750 assert_not_reached();
3757 static const char* const dns_transaction_state_table
[_DNS_TRANSACTION_STATE_MAX
] = {
3758 [DNS_TRANSACTION_NULL
] = "null",
3759 [DNS_TRANSACTION_PENDING
] = "pending",
3760 [DNS_TRANSACTION_VALIDATING
] = "validating",
3761 [DNS_TRANSACTION_RCODE_FAILURE
] = "rcode-failure",
3762 [DNS_TRANSACTION_SUCCESS
] = "success",
3763 [DNS_TRANSACTION_NO_SERVERS
] = "no-servers",
3764 [DNS_TRANSACTION_TIMEOUT
] = "timeout",
3765 [DNS_TRANSACTION_ATTEMPTS_MAX_REACHED
] = "attempts-max-reached",
3766 [DNS_TRANSACTION_INVALID_REPLY
] = "invalid-reply",
3767 [DNS_TRANSACTION_ERRNO
] = "errno",
3768 [DNS_TRANSACTION_ABORTED
] = "aborted",
3769 [DNS_TRANSACTION_DNSSEC_FAILED
] = "dnssec-failed",
3770 [DNS_TRANSACTION_NO_TRUST_ANCHOR
] = "no-trust-anchor",
3771 [DNS_TRANSACTION_RR_TYPE_UNSUPPORTED
] = "rr-type-unsupported",
3772 [DNS_TRANSACTION_NETWORK_DOWN
] = "network-down",
3773 [DNS_TRANSACTION_NOT_FOUND
] = "not-found",
3774 [DNS_TRANSACTION_NO_SOURCE
] = "no-source",
3775 [DNS_TRANSACTION_STUB_LOOP
] = "stub-loop",
3777 DEFINE_STRING_TABLE_LOOKUP(dns_transaction_state
, DnsTransactionState
);
3779 static const char* const dns_transaction_source_table
[_DNS_TRANSACTION_SOURCE_MAX
] = {
3780 [DNS_TRANSACTION_NETWORK
] = "network",
3781 [DNS_TRANSACTION_CACHE
] = "cache",
3782 [DNS_TRANSACTION_ZONE
] = "zone",
3783 [DNS_TRANSACTION_TRUST_ANCHOR
] = "trust-anchor",
3785 DEFINE_STRING_TABLE_LOOKUP(dns_transaction_source
, DnsTransactionSource
);